diff --git a/backend/signal_engine.py b/backend/signal_engine.py
index 5082f08..0324011 100644
--- a/backend/signal_engine.py
+++ b/backend/signal_engine.py
@@ -317,8 +317,8 @@ class SymbolState:
         self.last_signal_dir: dict[str, str] = {}
         self.recent_large_trades: deque = deque()
         # ── Phase 2 实时内存字段（由后台WebSocket协程更新）──────────
-        self.rt_obi: float = 0.0               # 订单簿失衡[-1,1]
-        self.rt_spot_perp_div: float = 0.0     # 期现背离（spot-mark)/mark
+        self.rt_obi: float = 0.0               # 订单簿失衡[-1,1]（实时WebSocket，所有symbol）
+        self.rt_spot_perp_div: float = 0.0     # 期现背离（spot-mark)/mark（实时WebSocket，所有symbol）
         # tiered_cvd_whale：按成交额分档，实时累计（最近15分钟窗口）
         self._whale_trades: deque = deque()    # (time_ms, usd_val, is_sell)
         self.WHALE_WINDOW_MS: int = 15 * 60 * 1000  # 15分钟
@@ -753,6 +753,20 @@ class SymbolState:
         last_signal_ts = self.last_signal_ts.get(strategy_name, 0)
         in_cooldown = now_ms - last_signal_ts < COOLDOWN_MS
 
+        # ── Per-symbol 四门参数（从 strategy_cfg.symbol_gates 读取）──────────
+        symbol_gates = (strategy_cfg.get("symbol_gates") or {}).get(self.symbol, {})
+        min_vol      = float(symbol_gates.get("min_vol_threshold", 0.003))
+        whale_usd    = float(symbol_gates.get("whale_threshold_usd", 50000))
+        obi_veto     = float(symbol_gates.get("obi_veto_threshold", 0.35))
+        spd_veto     = float(symbol_gates.get("spot_perp_divergence_veto", 0.005))
+
+        gate_block = None  # 门控否决原因，None = 全部通过
+
+        # 门1：波动率下限
+        atr_pct_price = atr / price if price > 0 else 0
+        if atr_pct_price < min_vol:
+            gate_block = f"low_vol({atr_pct_price:.4f}<{min_vol})"
+
         # ── Direction Layer（55分）──────────────────────────────────
         # cvd_resonance（30分）：fast+mid同向 = 有效方向
         if cvd_fast > 0 and cvd_mid > 0:
@@ -768,6 +782,37 @@ class SymbolState:
             cvd_resonance = 0
             no_direction = True   # gate: 方向不一致 → 直接不开仓
 
+        # 门2：鲸鱼推力（大单净方向需与信号方向一致）
+        if not gate_block and not no_direction:
+            whale_aligned = any(
+                (direction == "LONG" and lt[2] == 0 and lt[1] * price >= whale_usd) or
+                (direction == "SHORT" and lt[2] == 1 and lt[1] * price >= whale_usd)
+                for lt in self.recent_large_trades
+            )
+            whale_adverse = any(
+                (direction == "LONG" and lt[2] == 1 and lt[1] * price >= whale_usd) or
+                (direction == "SHORT" and lt[2] == 0 and lt[1] * price >= whale_usd)
+                for lt in self.recent_large_trades
+            )
+            # 有明确对立大单时否决（没有大单时不否决，给机会）
+            if whale_adverse and not whale_aligned:
+                gate_block = f"whale_adverse(>${whale_usd/1000:.0f}k)"
+
+        # 门3：OBI否决（优先实时WebSocket值，fallback DB）
+        obi_raw = self.rt_obi if self.rt_obi != 0.0 else to_float(self.market_indicators.get("obi_depth_10"))
+        if not gate_block and not no_direction and obi_raw is not None:
+            if direction == "LONG" and obi_raw < -obi_veto:
+                gate_block = f"obi_veto({obi_raw:.3f}<-{obi_veto})"
+            elif direction == "SHORT" and obi_raw > obi_veto:
+                gate_block = f"obi_veto({obi_raw:.3f}>{obi_veto})"
+
+        # 门4：期现背离否决（优先实时WebSocket值，fallback DB）
+        spot_perp_div = self.rt_spot_perp_div if self.rt_spot_perp_div != 0.0 else to_float(self.market_indicators.get("spot_perp_divergence"))
+        if not gate_block and not no_direction and spot_perp_div is not None:
+            if (direction == "LONG" and spot_perp_div < -spd_veto) or \
+               (direction == "SHORT" and spot_perp_div > spd_veto):
+                gate_block = f"spd_veto({spot_perp_div:.4f})"
+
         # p99_flow_alignment（0/10/20分）
         has_adverse_p99 = any(
             (direction == "LONG" and lt[2] == 1) or (direction == "SHORT" and lt[2] == 0)
@@ -833,12 +878,22 @@ class SymbolState:
         total_score = min(direction_score + crowding_score + environment_score + aux_score, 100)
         total_score = max(0, round(total_score, 1))
 
+        # 门控否决时归零分、清方向
+        gate_passed = gate_block is None
+        if not gate_passed:
+            total_score = 0
+
         result.update({
             "score": total_score,
-            "direction": direction if not no_direction else None,
+            "direction": direction if (not no_direction and gate_passed) else None,
             "atr_value": atr_value,
             "factors": {
                 "track": "ALT",
+                "gate_passed": gate_passed,
+                "gate_block": gate_block,
+                "atr_pct_price": round(atr_pct_price, 5),
+                "obi_raw": obi_raw,
+                "spot_perp_div": spot_perp_div,
                 "direction": {
                     "score": direction_score, "max": 55,
                     "cvd_resonance": cvd_resonance, "p99_flow": p99_flow, "accel_bonus": accel_bonus,
@@ -852,7 +907,7 @@ class SymbolState:
             },
         })
 
-        if not no_direction and not in_cooldown:
+        if not no_direction and gate_passed and not in_cooldown:
             if total_score >= flip_threshold:
                 result["signal"] = direction
                 result["tier"] = "heavy"
@@ -1314,14 +1369,15 @@ async def _ws_spot_perp_stream(symbol: str, state):
     await asyncio.gather(read_spot(), read_perp())
 
 async def _realtime_ws_runner(states: dict):
-    """统一启动所有实时WebSocket协程，目前只给BTC"""
-    btc_state = states.get("BTCUSDT")
-    if btc_state is None:
-        return
-    await asyncio.gather(
-        _ws_obi_stream("BTCUSDT", btc_state),
-        _ws_spot_perp_stream("BTCUSDT", btc_state),
-    )
+    """统一启动所有实时WebSocket协程，BTC + ALT (ETH/XRP/SOL)"""
+    coros = []
+    for sym, state in states.items():
+        # OBI流：所有symbol都接（perp depth10）
+        coros.append(_ws_obi_stream(sym, state))
+        # 期现背离流：只有有现货+合约的币种（BTC/ETH/XRP/SOL都有）
+        coros.append(_ws_spot_perp_stream(sym, state))
+    if coros:
+        await asyncio.gather(*coros)
 
 def start_realtime_ws(states: dict):
     """在独立线程里跑asyncio event loop，驱动实时WebSocket采集"""
diff --git a/backend/strategies/v53_alt.json b/backend/strategies/v53_alt.json
index b5468ee..6b424c7 100644
--- a/backend/strategies/v53_alt.json
+++ b/backend/strategies/v53_alt.json
@@ -2,7 +2,7 @@
   "name": "v53_alt",
   "version": "5.3",
   "track": "ALT",
-  "description": "V5.3 ALT轨（ETH/XRP/SOL）: 55/25/15/5权重，删除确认层（解决CVD双重计分），独立BTC走gate-control",
+  "description": "V5.3 ALT轨（ETH/XRP/SOL）: 55/25/15/5权重，删除确认层，per-symbol四门控制",
   "threshold": 75,
   "flip_threshold": 85,
   "weights": {
@@ -28,5 +28,25 @@
     "tp_maker": true
   },
   "symbols": ["ETHUSDT", "XRPUSDT", "SOLUSDT"],
-  "signals": ["cvd", "p99", "accel", "ls_ratio", "top_trader", "oi", "coinbase_premium"]
+  "signals": ["cvd", "p99", "accel", "ls_ratio", "top_trader", "oi", "coinbase_premium"],
+  "symbol_gates": {
+    "ETHUSDT": {
+      "min_vol_threshold": 0.003,
+      "whale_threshold_usd": 50000,
+      "obi_veto_threshold": 0.35,
+      "spot_perp_divergence_veto": 0.005
+    },
+    "SOLUSDT": {
+      "min_vol_threshold": 0.006,
+      "whale_threshold_usd": 20000,
+      "obi_veto_threshold": 0.45,
+      "spot_perp_divergence_veto": 0.008
+    },
+    "XRPUSDT": {
+      "min_vol_threshold": 0.004,
+      "whale_threshold_usd": 30000,
+      "obi_veto_threshold": 0.40,
+      "spot_perp_divergence_veto": 0.006
+    }
+  }
 }