diff --git a/lib/exchange/okx_options_lib.py b/lib/exchange/okx_options_lib.py
index 7ff93bf..5287260 100644
--- a/lib/exchange/okx_options_lib.py
+++ b/lib/exchange/okx_options_lib.py
@@ -793,7 +793,7 @@ def place_option_limit_order(
     if pos_side:
         body["posSide"] = pos_side
     if reduce_only:
-        body["reduceOnly"] = True
+        body["reduceOnly"] = "true"
     try:
         resp = ex.private_post_trade_order(body)
         data = (resp or {}).get("data") or []
@@ -829,7 +829,7 @@ def place_option_market_order(
     if pos_side:
         body["posSide"] = pos_side
     if reduce_only:
-        body["reduceOnly"] = True
+        body["reduceOnly"] = "true"
     try:
         resp = ex.private_post_trade_order(body)
         data = (resp or {}).get("data") or []
diff --git a/lib/options/options_target_lib.py b/lib/options/options_target_lib.py
index 19ac10d..7a9e192 100644
--- a/lib/options/options_target_lib.py
+++ b/lib/options/options_target_lib.py
@@ -273,9 +273,18 @@ def close_option_by_bid_depth(
         preview = estimate_close_by_bids(book.get("bids") or [], remaining, ct_mult=ct_mult)
         levels = preview.get("levels") or []
         if not levels:
-            # 无买盘时回退:报价买一 → 标记价 → 再查一次 quote
+            # 无买盘时回退:报价买一 → 报价标记价 → 持仓标记价
             q2 = cfg["quote_option_contract"](ex, inst_id)
-            fallback_px = _safe_float(q2.get("bid")) or _safe_float(q2.get("mark_px")) or _safe_float(q.get("bid")) or _safe_float(q.get("mark_px"))
+            cur_mark = _safe_float(cur_pos.get("markPx")) if cur_pos else None
+            pos_mark = _safe_float(pos.get("markPx"))
+            fallback_px = (
+                _safe_float(q2.get("bid"))
+                or _safe_float(q2.get("mark_px"))
+                or _safe_float(q.get("bid"))
+                or _safe_float(q.get("mark_px"))
+                or cur_mark
+                or pos_mark
+            )
             if fallback_px is None or fallback_px <= 0:
                 stopped_reason = "no_bid_depth"
                 break