diff --git a/backend/app/models/attribution_record.py b/backend/app/models/attribution_record.py
index 5e8f9dc..a288334 100644
--- a/backend/app/models/attribution_record.py
+++ b/backend/app/models/attribution_record.py
@@ -1,7 +1,7 @@
 import uuid
 from datetime import datetime
 
-from sqlalchemy import String, Float, Integer, ForeignKey, Index, func, Text
+from sqlalchemy import String, Float, Integer, DateTime, ForeignKey, Index, func, Text
 from sqlalchemy import Uuid
 from sqlalchemy.orm import Mapped, mapped_column, relationship
 
@@ -37,18 +37,20 @@ class AttributionRecord(Base):
     attribution_window_days: Mapped[int] = mapped_column(
         Integer, server_default="28", nullable=False,
     )
-    published_at: Mapped[datetime | None] = mapped_column(nullable=True)
-    window_end_at: Mapped[datetime | None] = mapped_column(nullable=True)
+    published_at: Mapped[datetime | None] = mapped_column(DateTime(timezone=True), nullable=True)
+    window_end_at: Mapped[datetime | None] = mapped_column(DateTime(timezone=True), nullable=True)
     status: Mapped[str] = mapped_column(
         String(20), server_default="tracking", nullable=False,
     )
     attributed_dimensions: Mapped[dict | None] = mapped_column(JSONType, nullable=True)
     roi_percentage: Mapped[float | None] = mapped_column(Float, nullable=True)
     created_at: Mapped[datetime] = mapped_column(
+        DateTime(timezone=True),
         server_default=func.now(),
         nullable=False,
     )
     updated_at: Mapped[datetime] = mapped_column(
+        DateTime(timezone=True),
         server_default=func.now(),
         onupdate=func.now(),
         nullable=False,
diff --git a/backend/app/models/brand.py b/backend/app/models/brand.py
index bd56c30..60e44f8 100644
--- a/backend/app/models/brand.py
+++ b/backend/app/models/brand.py
@@ -40,13 +40,15 @@ class Brand(Base):
     platforms: Mapped[list] = mapped_column(JSONType, default=list, nullable=False)
     frequency: Mapped[str] = mapped_column(String(20), default="weekly", nullable=False)
     status: Mapped[str] = mapped_column(String(20), default="active", nullable=False)
-    last_queried_at: Mapped[datetime | None] = mapped_column(DateTime, nullable=True)
-    next_query_at: Mapped[datetime | None] = mapped_column(DateTime, nullable=True)
+    last_queried_at: Mapped[datetime | None] = mapped_column(DateTime(timezone=True), nullable=True)
+    next_query_at: Mapped[datetime | None] = mapped_column(DateTime(timezone=True), nullable=True)
     created_at: Mapped[datetime] = mapped_column(
+        DateTime(timezone=True),
         server_default=func.now(),
         nullable=False,
     )
     updated_at: Mapped[datetime] = mapped_column(
+        DateTime(timezone=True),
         server_default=func.now(),
         onupdate=func.now(),
         nullable=False,
diff --git a/backend/app/models/brand_knowledge.py b/backend/app/models/brand_knowledge.py
index cca0887..0c3057a 100644
--- a/backend/app/models/brand_knowledge.py
+++ b/backend/app/models/brand_knowledge.py
@@ -1,7 +1,7 @@
 import uuid
 from datetime import datetime
 
-from sqlalchemy import String, Integer, Boolean, ForeignKey, Index, func, Text
+from sqlalchemy import String, Integer, Boolean, DateTime, ForeignKey, Index, func, Text
 from sqlalchemy import Uuid
 from sqlalchemy.orm import Mapped, mapped_column, relationship
 
@@ -32,10 +32,12 @@ class BrandKnowledge(Base):
         nullable=True,
     )
     created_at: Mapped[datetime] = mapped_column(
+        DateTime(timezone=True),
         server_default=func.now(),
         nullable=False,
     )
     updated_at: Mapped[datetime] = mapped_column(
+        DateTime(timezone=True),
         server_default=func.now(),
         onupdate=func.now(),
         nullable=False,
@@ -81,6 +83,7 @@ class Keyword(Base):
     competition_level: Mapped[str | None] = mapped_column(String(20), nullable=True)
     status: Mapped[str] = mapped_column(String(20), server_default="active", nullable=False)
     created_at: Mapped[datetime] = mapped_column(
+        DateTime(timezone=True),
         server_default=func.now(),
         nullable=False,
     )
diff --git a/backend/app/models/citation_record.py b/backend/app/models/citation_record.py
index 2bfca19..c691ef5 100644
--- a/backend/app/models/citation_record.py
+++ b/backend/app/models/citation_record.py
@@ -1,7 +1,7 @@
 import uuid
 from datetime import datetime
 
-from sqlalchemy import String, Boolean, Integer, Float, ForeignKey, Index, func, Text
+from sqlalchemy import String, Boolean, Integer, Float, DateTime, ForeignKey, Index, func, Text
 from sqlalchemy import Uuid, JSON
 from sqlalchemy.orm import Mapped, mapped_column, relationship
 
@@ -65,6 +65,7 @@ class CitationRecord(Base):
         comment="AI回答原始文本（去掉data_source标记后的纯文本）",
     )
     queried_at: Mapped[datetime] = mapped_column(
+        DateTime(timezone=True),
         server_default=func.now(),
         nullable=False,
     )
diff --git a/backend/app/models/competitor.py b/backend/app/models/competitor.py
index 46e9814..edb5a5d 100644
--- a/backend/app/models/competitor.py
+++ b/backend/app/models/competitor.py
@@ -37,6 +37,7 @@ class Competitor(Base):
     name: Mapped[str] = mapped_column(String(50), nullable=False)
     aliases: Mapped[list] = mapped_column(JSONType, default=list, nullable=False)
     created_at: Mapped[datetime] = mapped_column(
+        DateTime(timezone=True),
         server_default=func.now(),
         nullable=False,
     )
diff --git a/backend/app/models/competitor_insight.py b/backend/app/models/competitor_insight.py
index b5b1582..3595e61 100644
--- a/backend/app/models/competitor_insight.py
+++ b/backend/app/models/competitor_insight.py
@@ -1,7 +1,7 @@
 import uuid
 from datetime import datetime
 
-from sqlalchemy import String, Float, Integer, ForeignKey, Index, func
+from sqlalchemy import String, Float, Integer, DateTime, ForeignKey, Index, func
 from sqlalchemy import Uuid
 from sqlalchemy.dialects.postgresql import JSONB
 from sqlalchemy.orm import Mapped, mapped_column
@@ -49,10 +49,12 @@ class CompetitorInsight(Base):
     confidence: Mapped[str] = mapped_column(String(20), default="medium", nullable=False)
     period_days: Mapped[int] = mapped_column(Integer, default=30, nullable=False)
     created_at: Mapped[datetime] = mapped_column(
+        DateTime(timezone=True),
         server_default=func.now(),
         nullable=False,
     )
     updated_at: Mapped[datetime] = mapped_column(
+        DateTime(timezone=True),
         server_default=func.now(),
         onupdate=func.now(),
         nullable=False,
diff --git a/backend/app/models/content.py b/backend/app/models/content.py
index 8075c38..4c0d47e 100644
--- a/backend/app/models/content.py
+++ b/backend/app/models/content.py
@@ -1,7 +1,7 @@
 import uuid
 from datetime import datetime
 
-from sqlalchemy import String, Integer, ForeignKey, Index, func, Text
+from sqlalchemy import String, Integer, DateTime, ForeignKey, Index, func, Text
 from sqlalchemy import Uuid
 from sqlalchemy.orm import Mapped, mapped_column, relationship
 
@@ -40,10 +40,12 @@ class Content(Base):
     )
     current_version: Mapped[int] = mapped_column(Integer, server_default="1", nullable=False)
     created_at: Mapped[datetime] = mapped_column(
+        DateTime(timezone=True),
         server_default=func.now(),
         nullable=False,
     )
     updated_at: Mapped[datetime] = mapped_column(
+        DateTime(timezone=True),
         server_default=func.now(),
         onupdate=func.now(),
         nullable=False,
@@ -98,6 +100,7 @@ class ContentVersion(Base):
         nullable=True,
     )
     created_at: Mapped[datetime] = mapped_column(
+        DateTime(timezone=True),
         server_default=func.now(),
         nullable=False,
     )
@@ -137,6 +140,7 @@ class ContentReview(Base):
     status: Mapped[str] = mapped_column(String(20), nullable=False)
     comments: Mapped[str | None] = mapped_column(Text, nullable=True)
     created_at: Mapped[datetime] = mapped_column(
+        DateTime(timezone=True),
         server_default=func.now(),
         nullable=False,
     )
diff --git a/backend/app/models/distribution.py b/backend/app/models/distribution.py
index 9c1d142..b228f50 100644
--- a/backend/app/models/distribution.py
+++ b/backend/app/models/distribution.py
@@ -2,7 +2,7 @@
 import uuid
 from datetime import datetime
 
-from sqlalchemy import String, Integer, ForeignKey, Index, func, Text
+from sqlalchemy import String, Integer, DateTime, ForeignKey, Index, func, Text
 from sqlalchemy import Uuid
 from sqlalchemy.orm import Mapped, mapped_column, relationship
 
@@ -38,10 +38,12 @@ class DistributionSchedule(Base):
         nullable=True,
     )
     created_at: Mapped[datetime] = mapped_column(
+        DateTime(timezone=True),
         server_default=func.now(),
         nullable=False,
     )
     updated_at: Mapped[datetime] = mapped_column(
+        DateTime(timezone=True),
         server_default=func.now(),
         onupdate=func.now(),
         nullable=False,
diff --git a/backend/app/models/geo_plan.py b/backend/app/models/geo_plan.py
index 23c5f04..bfbd84e 100644
--- a/backend/app/models/geo_plan.py
+++ b/backend/app/models/geo_plan.py
@@ -1,7 +1,7 @@
 import uuid
 from datetime import datetime
 
-from sqlalchemy import String, Integer, Text, ForeignKey, Index, func
+from sqlalchemy import String, Integer, Text, DateTime, ForeignKey, Index, func
 from sqlalchemy import Uuid
 from sqlalchemy.orm import Mapped, mapped_column, relationship
 
@@ -41,10 +41,12 @@ class GeoPlan(Base):
         nullable=True,
     )
     created_at: Mapped[datetime] = mapped_column(
+        DateTime(timezone=True),
         server_default=func.now(),
         nullable=False,
     )
     updated_at: Mapped[datetime] = mapped_column(
+        DateTime(timezone=True),
         server_default=func.now(),
         onupdate=func.now(),
         nullable=False,
@@ -92,12 +94,14 @@ class GeoPlanAction(Base):
     sort_order: Mapped[int] = mapped_column(
         Integer, server_default="0", nullable=False,
     )
-    completed_at: Mapped[datetime | None] = mapped_column(nullable=True)
+    completed_at: Mapped[datetime | None] = mapped_column(DateTime(timezone=True), nullable=True)
     created_at: Mapped[datetime] = mapped_column(
+        DateTime(timezone=True),
         server_default=func.now(),
         nullable=False,
     )
     updated_at: Mapped[datetime] = mapped_column(
+        DateTime(timezone=True),
         server_default=func.now(),
         onupdate=func.now(),
         nullable=False,
diff --git a/backend/app/models/query.py b/backend/app/models/query.py
index d13478a..9ef182a 100644
--- a/backend/app/models/query.py
+++ b/backend/app/models/query.py
@@ -1,7 +1,7 @@
 import uuid
 from datetime import datetime
 
-from sqlalchemy import String, ForeignKey, Index, func
+from sqlalchemy import String, DateTime, ForeignKey, Index, func
 from sqlalchemy import Uuid, JSON
 from sqlalchemy.orm import Mapped, mapped_column, relationship
 
@@ -27,13 +27,15 @@ class Query(Base):
     platforms: Mapped[list] = mapped_column(JSON, nullable=False, default=lambda: ["wenxin", "kimi"])
     frequency: Mapped[str] = mapped_column(String(20), default="weekly")
     status: Mapped[str] = mapped_column(String(20), default="active")
-    last_queried_at: Mapped[datetime | None] = mapped_column(nullable=True)
-    next_query_at: Mapped[datetime | None] = mapped_column(nullable=True)
+    last_queried_at: Mapped[datetime | None] = mapped_column(DateTime(timezone=True), nullable=True)
+    next_query_at: Mapped[datetime | None] = mapped_column(DateTime(timezone=True), nullable=True)
     created_at: Mapped[datetime] = mapped_column(
+        DateTime(timezone=True),
         server_default=func.now(),
         nullable=False,
     )
     updated_at: Mapped[datetime] = mapped_column(
+        DateTime(timezone=True),
         server_default=func.now(),
         onupdate=func.now(),
         nullable=False,
diff --git a/backend/app/models/suggestion.py b/backend/app/models/suggestion.py
index 01efaeb..d48bbad 100644
--- a/backend/app/models/suggestion.py
+++ b/backend/app/models/suggestion.py
@@ -49,10 +49,12 @@ class Suggestion(Base):
         comment="状态: pending/in_progress/completed/dismissed",
     )
     generated_at: Mapped[datetime] = mapped_column(
+        DateTime(timezone=True),
         server_default=func.now(),
         nullable=False,
     )
     updated_at: Mapped[datetime] = mapped_column(
+        DateTime(timezone=True),
         server_default=func.now(),
         onupdate=func.now(),
         nullable=False,