diff --git a/backend/app/services/bitget_live_trading_service.py b/backend/app/services/bitget_live_trading_service.py
index ff755fb..fcbf357 100644
--- a/backend/app/services/bitget_live_trading_service.py
+++ b/backend/app/services/bitget_live_trading_service.py
@@ -84,6 +84,7 @@ class BitgetLiveTradingService:
             }
         """
         balance = self.trading_api.get_balance()
+        logger.debug(f"[Bitget] get_balance 原始返回: {balance}")
 
         usdt = balance.get('USDT', {})
         available = float(usdt.get('available', 0) or 0)
@@ -91,6 +92,11 @@ class BitgetLiveTradingService:
         equity = float(usdt.get('equity', 0) or 0)
         account_value = equity if equity > 0 else (available + frozen)
 
+        logger.info(
+            f"[Bitget] 账户状态: available=${available:.2f}, "
+            f"frozen=${frozen:.2f}, equity=${equity:.2f}, account_value=${account_value:.2f}"
+        )
+
         return {
             "account_value": account_value,
             "current_balance": account_value,
diff --git a/backend/app/services/bitget_trading_api_sdk.py b/backend/app/services/bitget_trading_api_sdk.py
index 6fe2f35..57cb507 100644
--- a/backend/app/services/bitget_trading_api_sdk.py
+++ b/backend/app/services/bitget_trading_api_sdk.py
@@ -699,13 +699,43 @@ class BitgetTradingAPI:
         查询账户余额
 
         Returns:
-            余额信息 {USDT: {available: "...", frozen: "...", locked: "..."}}
+            余额信息 {USDT: {available: "...", frozen: "...", locked: "...", equity: "..."}}
+
+        查询策略：
+        1. 优先使用 ccxt 统一接口 fetch_balance()，兼容 UTA / 经典账户
+        2. fetch_balance() 失败时，按 use_unified_account 回退到原始 API
         """
+        # ---------- 策略 1: ccxt fetch_balance ----------
+        try:
+            balance = self.exchange.fetch_balance({'type': 'swap'})
+            if balance and isinstance(balance, dict):
+                usdt_info = balance.get('USDT')
+                if usdt_info and isinstance(usdt_info, dict):
+                    available = usdt_info.get('free', 0) or 0
+                    used = usdt_info.get('used', 0) or 0
+                    total = usdt_info.get('total', 0) or 0
+                    result = {
+                        'USDT': {
+                            'available': str(available),
+                            'frozen': str(used),
+                            'locked': str(used),
+                            'equity': str(total if total else (available + used)),
+                        }
+                    }
+                    logger.debug(f"[fetch_balance] USDT available={available}, used={used}, total={total}")
+                    return result
+                else:
+                    logger.warning(f"[fetch_balance] 返回中无 USDT 字段: {list(balance.keys())[:10]}")
+        except Exception as e:
+            logger.warning(f"[fetch_balance] 查询失败，回退到原始 API: {e}")
+
+        # ---------- 策略 2: 原始 API（UTA / 合约账户） ----------
         try:
             if self.use_unified_account:
                 response = self.exchange.privateUtaGetV3AccountAssets({
                     'coin': self.DEFAULT_MARGIN_COIN,
                 })
+                logger.debug(f"[UTA API] 原始响应: {response}")
                 assets = response.get('data', {}).get('assets', []) or []
                 result = {}
                 for entry in assets:
@@ -718,12 +748,13 @@ class BitgetTradingAPI:
                         'locked': str(entry.get('locked', '0')),
                         'equity': str(entry.get('equity', entry.get('balance', '0'))),
                     }
-                logger.debug(f"账户余额: {result}")
+                logger.debug(f"[UTA API] 账户余额: {result}")
                 return result
 
             response = self.exchange.privateMixGetV2MixAccountAccounts({
                 'productType': self.DEFAULT_PRODUCT_TYPE,
             })
+            logger.debug(f"[合约 API] 原始响应: {response}")
 
             result = {}
             for entry in response.get('data', []) or []:
@@ -737,7 +768,7 @@ class BitgetTradingAPI:
                     'equity': str(entry.get('accountEquity', entry.get('usdtEquity', '0'))),
                 }
 
-            logger.debug(f"账户余额: {result}")
+            logger.debug(f"[合约 API] 账户余额: {result}")
             return result
 
         except ccxt.BaseError as e:
diff --git a/backend/tests/test_bitget_balance.py b/backend/tests/test_bitget_balance.py
new file mode 100644
index 0000000..85dacbb
--- /dev/null
+++ b/backend/tests/test_bitget_balance.py
@@ -0,0 +1,356 @@
+"""
+BitgetTradingAPI.get_balance() 单元测试
+
+覆盖场景：
+  1. fetch_balance 成功 → 直接返回（不调原始 API）
+  2. fetch_balance 无 USDT → 回退到原始 API (UTA)
+  3. fetch_balance 无 USDT → 回退到原始 API (合约)
+  4. fetch_balance 抛异常 → 回退到原始 API (UTA)
+  5. fetch_balance 和原始 API 都失败 → 返回 {}
+  6. 余额为 0 / None 的边界情况
+  7. get_account_state 端到端解析
+"""
+import importlib.util
+import os
+import sys
+import types
+from pathlib import Path
+from unittest.mock import MagicMock, patch
+
+sys.path.insert(0, os.path.join(os.path.dirname(__file__), '..'))
+
+
+def load_bitget_sdk_class():
+    sdk_path = (
+        Path(__file__).resolve().parents[1]
+        / 'app' / 'services' / 'bitget_trading_api_sdk.py'
+    )
+
+    if 'ccxt' not in sys.modules:
+        ccxt_module = types.ModuleType('ccxt')
+        ccxt_module.BaseError = Exception
+        ccxt_module.bitget = MagicMock()
+        sys.modules['ccxt'] = ccxt_module
+
+    # mock app.config
+    if 'app.config' not in sys.modules:
+        mock_cfg = types.ModuleType('app.config')
+        mock_cfg.get_settings = MagicMock()
+        sys.modules['app.config'] = mock_cfg
+
+    # mock app.utils.logger
+    if 'app.utils.logger' not in sys.modules:
+        mock_log = types.ModuleType('app.utils.logger')
+        mock_log.logger = MagicMock()
+        sys.modules['app.utils.logger'] = mock_log
+
+    module_name = 'app.services.bitget_trading_api_sdk_bal_test'
+    spec = importlib.util.spec_from_file_location(module_name, sdk_path)
+    module = importlib.util.module_from_spec(spec)
+    sys.modules[module_name] = module
+    spec.loader.exec_module(module)
+    return module.BitgetTradingAPI
+
+
+# ──────────────────────────────────────────────
+# 测试 1: fetch_balance 成功，直接返回
+# ──────────────────────────────────────────────
+def test_fetch_balance_success():
+    """fetch_balance 返回 USDT，不走原始 API"""
+    BitgetTradingAPI = load_bitget_sdk_class()
+    api = BitgetTradingAPI.__new__(BitgetTradingAPI)
+    api.exchange = MagicMock()
+    api.use_unified_account = True
+
+    api.exchange.fetch_balance.return_value = {
+        'USDT': {'free': 1975.0, 'used': 50.0, 'total': 2025.0},
+        'free': {'USDT': 1975.0},
+        'used': {'USDT': 50.0},
+        'total': {'USDT': 2025.0},
+    }
+
+    balance = api.get_balance()
+
+    assert balance == {
+        'USDT': {
+            'available': '1975.0',
+            'frozen': '50.0',
+            'locked': '50.0',
+            'equity': '2025.0',
+        }
+    }
+    # 不应调原始 API
+    api.exchange.privateUtaGetV3AccountAssets.assert_not_called()
+
+
+# ──────────────────────────────────────────────
+# 测试 2: fetch_balance 成功，余额为 0
+# ──────────────────────────────────────────────
+def test_fetch_balance_zero_balance():
+    """fetch_balance 返回 0 余额，应正确解析"""
+    BitgetTradingAPI = load_bitget_sdk_class()
+    api = BitgetTradingAPI.__new__(BitgetTradingAPI)
+    api.exchange = MagicMock()
+    api.use_unified_account = True
+
+    api.exchange.fetch_balance.return_value = {
+        'USDT': {'free': 0, 'used': 0, 'total': 0},
+    }
+
+    balance = api.get_balance()
+
+    assert balance['USDT']['available'] == '0'
+    assert balance['USDT']['equity'] == '0'
+
+
+# ──────────────────────────────────────────────
+# 测试 3: fetch_balance 无 USDT → 回退 UTA
+# ──────────────────────────────────────────────
+def test_fetch_balance_no_usdt_fallback_uta():
+    """fetch_balance 返回无 USDT → 回退到 UTA 原始 API"""
+    BitgetTradingAPI = load_bitget_sdk_class()
+    api = BitgetTradingAPI.__new__(BitgetTradingAPI)
+    api.exchange = MagicMock()
+    api.use_unified_account = True
+
+    # fetch_balance 没有USDT
+    api.exchange.fetch_balance.return_value = {
+        'BTC': {'free': 0.5, 'used': 0, 'total': 0.5},
+    }
+
+    # UTA 回退返回正常数据
+    api.exchange.privateUtaGetV3AccountAssets.return_value = {
+        'code': '00000',
+        'data': {
+            'assets': [
+                {
+                    'coin': 'USDT',
+                    'available': '1975.00',
+                    'locked': '0',
+                    'equity': '1975.00',
+                }
+            ],
+        },
+    }
+
+    balance = api.get_balance()
+
+    assert balance['USDT']['available'] == '1975.00'
+    assert balance['USDT']['equity'] == '1975.00'
+    api.exchange.privateUtaGetV3AccountAssets.assert_called_once()
+
+
+# ──────────────────────────────────────────────
+# 测试 4: fetch_balance 无 USDT → 回退合约 API
+# ──────────────────────────────────────────────
+def test_fetch_balance_no_usdt_fallback_contract():
+    """use_unified_account=False → 回退到合约 API"""
+    BitgetTradingAPI = load_bitget_sdk_class()
+    api = BitgetTradingAPI.__new__(BitgetTradingAPI)
+    api.exchange = MagicMock()
+    api.use_unified_account = False
+
+    # fetch_balance 没有USDT
+    api.exchange.fetch_balance.return_value = {}
+
+    # 合约 API 回退
+    api.exchange.privateMixGetV2MixAccountAccounts.return_value = {
+        'code': '00000',
+        'data': [
+            {
+                'marginCoin': 'USDT',
+                'available': '800.50',
+                'locked': '100.00',
+                'accountEquity': '900.50',
+            }
+        ],
+    }
+
+    balance = api.get_balance()
+
+    assert balance['USDT']['available'] == '800.50'
+    assert balance['USDT']['frozen'] == '100.00'
+    assert balance['USDT']['equity'] == '900.50'
+
+
+# ──────────────────────────────────────────────
+# 测试 5: fetch_balance 抛异常 → 回退 UTA
+# ──────────────────────────────────────────────
+def test_fetch_balance_exception_fallback():
+    """fetch_balance 抛异常 → 回退到原始 API"""
+    BitgetTradingAPI = load_bitget_sdk_class()
+    api = BitgetTradingAPI.__new__(BitgetTradingAPI)
+    api.exchange = MagicMock()
+    api.use_unified_account = True
+
+    api.exchange.fetch_balance.side_effect = Exception("network error")
+
+    api.exchange.privateUtaGetV3AccountAssets.return_value = {
+        'code': '00000',
+        'data': {
+            'assets': [
+                {
+                    'coin': 'USDT',
+                    'available': '500.00',
+                    'locked': '0',
+                    'equity': '500.00',
+                }
+            ],
+        },
+    }
+
+    balance = api.get_balance()
+
+    assert balance['USDT']['available'] == '500.00'
+    api.exchange.privateUtaGetV3AccountAssets.assert_called_once()
+
+
+# ──────────────────────────────────────────────
+# 测试 6: 两个策略都失败 → 返回 {}
+# ──────────────────────────────────────────────
+def test_both_strategies_fail():
+    """fetch_balance 和原始 API 都失败 → 返回空字典"""
+    BitgetTradingAPI = load_bitget_sdk_class()
+    api = BitgetTradingAPI.__new__(BitgetTradingAPI)
+    api.exchange = MagicMock()
+    api.use_unified_account = True
+
+    api.exchange.fetch_balance.side_effect = Exception("timeout")
+    api.exchange.privateUtaGetV3AccountAssets.side_effect = Exception("auth fail")
+
+    balance = api.get_balance()
+
+    assert balance == {}
+
+
+# ──────────────────────────────────────────────
+# 测试 7: fetch_balance 返回 free=None
+# ──────────────────────────────────────────────
+def test_fetch_balance_none_values():
+    """fetch_balance 中 free/used 为 None → 解析为 0"""
+    BitgetTradingAPI = load_bitget_sdk_class()
+    api = BitgetTradingAPI.__new__(BitgetTradingAPI)
+    api.exchange = MagicMock()
+    api.use_unified_account = True
+
+    api.exchange.fetch_balance.return_value = {
+        'USDT': {'free': None, 'used': None, 'total': None},
+    }
+
+    balance = api.get_balance()
+
+    assert balance['USDT']['available'] == '0'
+    assert balance['USDT']['frozen'] == '0'
+    assert balance['USDT']['equity'] == '0'
+
+
+# ──────────────────────────────────────────────
+# 测试 8: fetch_balance 返回 free=0, total=0 → equity 用 free+used
+# ──────────────────────────────────────────────
+def test_fetch_balance_zero_total():
+    """total=0 时 equity = free + used"""
+    BitgetTradingAPI = load_bitget_sdk_class()
+    api = BitgetTradingAPI.__new__(BitgetTradingAPI)
+    api.exchange = MagicMock()
+    api.use_unified_account = True
+
+    api.exchange.fetch_balance.return_value = {
+        'USDT': {'free': 100, 'used': 50, 'total': 0},
+    }
+
+    balance = api.get_balance()
+
+    assert balance['USDT']['equity'] == '150'
+
+
+# ──────────────────────────────────────────────
+# 测试 9: UTA 返回空 assets → 回退到 {}
+# ──────────────────────────────────────────────
+def test_uta_empty_assets():
+    """UTA API 返回空 assets 列表"""
+    BitgetTradingAPI = load_bitget_sdk_class()
+    api = BitgetTradingAPI.__new__(BitgetTradingAPI)
+    api.exchange = MagicMock()
+    api.use_unified_account = True
+
+    api.exchange.fetch_balance.return_value = {}
+    api.exchange.privateUtaGetV3AccountAssets.return_value = {
+        'code': '00000',
+        'data': {'assets': []},
+    }
+
+    balance = api.get_balance()
+
+    assert balance == {}
+
+
+# ──────────────────────────────────────────────
+# 测试 10: get_account_state 端到端解析
+# ──────────────────────────────────────────────
+def test_get_account_state_e2e():
+    """get_account_state 正确解析 balance 返回值"""
+    BitgetTradingAPI = load_bitget_sdk_class()
+
+    # Mock get_bitget_live_service 的依赖链
+    # 直接测 get_account_state 解析逻辑
+    from app.services.bitget_live_trading_service import CONTRACT_SIZES
+
+    # 模拟 balance 返回
+    balance_return = {
+        'USDT': {
+            'available': '1975.50',
+            'frozen': '24.50',
+            'locked': '24.50',
+            'equity': '2000.00',
+        }
+    }
+
+    # 直接验证解析逻辑（不初始化完整 service）
+    usdt = balance_return.get('USDT', {})
+    available = float(usdt.get('available', 0) or 0)
+    frozen = float(usdt.get('frozen', 0) or 0)
+    equity = float(usdt.get('equity', 0) or 0)
+    account_value = equity if equity > 0 else (available + frozen)
+
+    assert available == 1975.50
+    assert frozen == 24.50
+    assert equity == 2000.00
+    assert account_value == 2000.00
+
+
+# ──────────────────────────────────────────────
+# 测试 11: balance 返回 {} 时 get_account_state 各字段为 0
+# ──────────────────────────────────────────────
+def test_get_account_state_empty_balance():
+    """balance 返回空 → 全部为 0"""
+    balance_return = {}
+
+    usdt = balance_return.get('USDT', {})
+    available = float(usdt.get('available', 0) or 0)
+    frozen = float(usdt.get('frozen', 0) or 0)
+    equity = float(usdt.get('equity', 0) or 0)
+    account_value = equity if equity > 0 else (available + frozen)
+
+    assert available == 0.0
+    assert frozen == 0.0
+    assert account_value == 0.0
+
+
+# ──────────────────────────────────────────────
+# 测试 12: fetch_balance 返回字符串数值
+# ──────────────────────────────────────────────
+def test_fetch_balance_string_values():
+    """ccxt 有时返回字符串类型的余额"""
+    BitgetTradingAPI = load_bitget_sdk_class()
+    api = BitgetTradingAPI.__new__(BitgetTradingAPI)
+    api.exchange = MagicMock()
+    api.use_unified_account = True
+
+    api.exchange.fetch_balance.return_value = {
+        'USDT': {'free': '1975.50', 'used': '24.50', 'total': '2000.00'},
+    }
+
+    balance = api.get_balance()
+
+    assert balance['USDT']['available'] == '1975.50'
+    assert balance['USDT']['equity'] == '2000.00'