diff --git a/app/models.py b/app/models.py
index be4d276..84c4a65 100644
--- a/app/models.py
+++ b/app/models.py
@@ -1,8 +1,8 @@
 import uuid
 from datetime import datetime, timezone
 
-from sqlalchemy import Column, DateTime, ForeignKey, Integer, String
-from sqlalchemy.orm import relationship
+from sqlalchemy import Column, DateTime, ForeignKey, Integer, String, event
+from sqlalchemy.orm import relationship, validates
 
 from app.database import Base
 
@@ -72,3 +72,7 @@ class Postcard(Base):
     updated_at = Column(DateTime, default=_utcnow, onupdate=_utcnow)
 
     profile = relationship("Profile", back_populates="postcards")
+
+    @validates("country")
+    def _upper_country(self, key, value):
+        return value.strip().upper() if value else None
diff --git a/app/routers/web.py b/app/routers/web.py
index 45c2f62..267b1b5 100644
--- a/app/routers/web.py
+++ b/app/routers/web.py
@@ -221,7 +221,7 @@ def postcard_create(
         card_number=card_number,
         status=status,
         recipient_name=recipient_name or None,
-        country=country or None,
+        country=(country.strip().upper() if country else None),
         send_time=_parse_dt(send_time),
         arrival_time=_parse_dt(arrival_time),
         sender_name=sender_name or None,
diff --git a/app/templates/postcard_form.html b/app/templates/postcard_form.html
index 41a021a..94d9cc8 100644
--- a/app/templates/postcard_form.html
+++ b/app/templates/postcard_form.html
@@ -19,7 +19,7 @@
         <label>收件人 *</label>
         <input type="text" name="recipient_name" id="input-recipient" value="{{ postcard.recipient_name if postcard else '' }}">
         <label>国家/地区 *</label>
-        <input type="text" name="country" id="input-country" value="{{ postcard.country if postcard else '' }}" maxlength="2" placeholder="JP" style="width:80px;text-transform:uppercase">
+        <input type="text" name="country" id="input-country" value="{{ postcard.country if postcard else '' }}" maxlength="2" placeholder="JP" style="width:80px;text-transform:uppercase" oninput="this.value=this.value.toUpperCase()">
         <label>寄出时间 *</label>
         <input type="date" name="send_time" id="input-send-time" value="{{ postcard.send_time.strftime('%Y-%m-%d') if postcard and postcard.send_time else '' }}">
         <label id="label-arrival">到达时间</label>