diff --git a/backend/app/models/message.py b/backend/app/models/message.py
index 71102da..e0d1604 100644
--- a/backend/app/models/message.py
+++ b/backend/app/models/message.py
@@ -6,6 +6,7 @@ from sqlalchemy.dialects.postgresql import UUID
 from sqlalchemy.orm import Mapped, mapped_column
 
 from app.models.base import Base
+from app.core.time_utils import get_beijing_time
 
 
 class ProductMessage(Base):
@@ -28,5 +29,5 @@ class ProductMessage(Base):
         Text, nullable=False, comment="留言内容",
     )
     created_at: Mapped[datetime] = mapped_column(
-        DateTime, default=datetime.utcnow, comment="留言时间",
+        DateTime(timezone=True), default=get_beijing_time, comment="留言时间（北京时间）",
     )
diff --git a/backend/app/services/dashboard_service.py b/backend/app/services/dashboard_service.py
index 127fdab..0581912 100644
--- a/backend/app/services/dashboard_service.py
+++ b/backend/app/services/dashboard_service.py
@@ -226,8 +226,13 @@ async def search_product_messages(
     items: list[ProductMessageItem] = []
     for msg, sn, mat_name in rows:
         t = msg.created_at
-        if t and t.tzinfo is None:
-            t = t.replace(tzinfo=BEIJING_TZ)
+        if t:
+            if t.tzinfo is None:
+                # 旧数据（datetime.utcnow）：naive UTC → 转北京时间
+                from datetime import timezone as dt_timezone
+                t = t.replace(tzinfo=dt_timezone.utc).astimezone(BEIJING_TZ)
+            else:
+                t = t.astimezone(BEIJING_TZ)
         time_str = t.isoformat() if t else ""
 
         items.append(ProductMessageItem(