diff --git a/inventory-backend/app/services/inbound/buy_service.py b/inventory-backend/app/services/inbound/buy_service.py
index 8035957..8d12fa4 100644
--- a/inventory-backend/app/services/inbound/buy_service.py
+++ b/inventory-backend/app/services/inbound/buy_service.py
@@ -12,6 +12,7 @@ import traceback
 import json
 import numpy as np
 from app.utils.ai_vision import extract_and_embed
+from app.utils.warehouse_location import material_company, usable_locations
 from app.services.image_embedding_service import ImageEmbeddingService
 
 
@@ -690,6 +691,15 @@ class BuyInboundService:
         if not candidates:
             return ""
 
-        # 按时间倒序排序，返回最新的库位
+        # 按时间倒序排序
         candidates.sort(key=lambda x: x[0] if x[0] else datetime.min, reverse=True)
-        return candidates[0][1] if candidates[0][1] else ""
+
+        # ★ 回填前校验：历史库位可能已被删除、或属于别家公司。不过滤的话，
+        #   操作员会在不知情的情况下把货记到一个不属于本公司的库位上。
+        #   按时间从新到旧挑第一个仍可用的；全都不合法则返回空串（表单不预填）。
+        ordered = [loc for _, loc in candidates if loc]
+        usable = set(usable_locations(material_company(base_id), ordered))
+        for loc in ordered:
+            if loc in usable:
+                return loc
+        return ""
diff --git a/inventory-backend/app/services/inbound/product_service.py b/inventory-backend/app/services/inbound/product_service.py
index a08d2b1..61c4508 100644
--- a/inventory-backend/app/services/inbound/product_service.py
+++ b/inventory-backend/app/services/inbound/product_service.py
@@ -12,6 +12,7 @@ import traceback
 import json
 import numpy as np
 from app.utils.ai_vision import extract_and_embed
+from app.utils.warehouse_location import material_company, usable_locations
 from app.services.image_embedding_service import ImageEmbeddingService
 from app.services.track_webhook_service import notify_track, get_current_operator
 
@@ -724,6 +725,15 @@ class ProductInboundService:
         if not candidates:
             return ""
 
-        # 按时间倒序排序，返回最新的库位
+        # 按时间倒序排序
         candidates.sort(key=lambda x: x[0] if x[0] else datetime.min, reverse=True)
-        return candidates[0][1] if candidates[0][1] else ""
+
+        # ★ 回填前校验：历史库位可能已被删除、或属于别家公司。不过滤的话，
+        #   操作员会在不知情的情况下把货记到一个不属于本公司的库位上。
+        #   按时间从新到旧挑第一个仍可用的；全都不合法则返回空串（表单不预填）。
+        ordered = [loc for _, loc in candidates if loc]
+        usable = set(usable_locations(material_company(base_id), ordered))
+        for loc in ordered:
+            if loc in usable:
+                return loc
+        return ""
diff --git a/inventory-backend/app/services/inbound/semi_service.py b/inventory-backend/app/services/inbound/semi_service.py
index 1e0fc7a..efb620e 100644
--- a/inventory-backend/app/services/inbound/semi_service.py
+++ b/inventory-backend/app/services/inbound/semi_service.py
@@ -12,6 +12,7 @@ import traceback
 import json
 import numpy as np
 from app.utils.ai_vision import extract_and_embed
+from app.utils.warehouse_location import material_company, usable_locations
 from app.services.image_embedding_service import ImageEmbeddingService
 from app.services.track_webhook_service import notify_track, get_current_operator
 
@@ -802,6 +803,15 @@ class SemiInboundService:
         if not candidates:
             return ""
 
-        # 按时间倒序排序，返回最新的库位
+        # 按时间倒序排序
         candidates.sort(key=lambda x: x[0] if x[0] else datetime.min, reverse=True)
-        return candidates[0][1] if candidates[0][1] else ""
+
+        # ★ 回填前校验：历史库位可能已被删除、或属于别家公司。不过滤的话，
+        #   操作员会在不知情的情况下把货记到一个不属于本公司的库位上。
+        #   按时间从新到旧挑第一个仍可用的；全都不合法则返回空串（表单不预填）。
+        ordered = [loc for _, loc in candidates if loc]
+        usable = set(usable_locations(material_company(base_id), ordered))
+        for loc in ordered:
+            if loc in usable:
+                return loc
+        return ""