diff --git a/backend/routers/config.py b/backend/routers/config.py
index c18a33a..8ee8562 100644
--- a/backend/routers/config.py
+++ b/backend/routers/config.py
@@ -2,6 +2,7 @@
 import asyncio
 import json
 import os
+import re
 import shutil
 import zipfile
 from datetime import datetime
@@ -501,19 +502,18 @@ async def get_versions():
 
 @router.put("/versions")
 async def update_versions(data: dict):
-    """更新 App_Ver 和 Build_Ver"""
+    """更新 App_Ver，并将 Build_Ver 重置为对应的 .0。"""
     app_ver = data.get("app_ver", "").strip()
-    build_ver = data.get("build_ver", "").strip()
+    if not re.fullmatch(r"\d+\.\d+\.\d+", app_ver):
+        raise HTTPException(status_code=400, detail="App_Ver 必须为主版本.次版本.修订号，例如 2.196.0")
 
-    if not app_ver or not build_ver:
-        raise HTTPException(status_code=400, detail="版本号不能为空")
-
-    config = load_config()
-    config["versions"] = {
-        "app_ver": app_ver,
-        "build_ver": build_ver,
-    }
+    build_ver = f"{app_ver}.0"
     async with _config_lock:
+        config = load_config()
+        config["versions"] = {
+            "app_ver": app_ver,
+            "build_ver": build_ver,
+        }
         save_config(config)
 
     return {"message": "版本号已更新", "app_ver": app_ver, "build_ver": build_ver}
diff --git a/frontend/src/__tests__/ConfigView.test.js b/frontend/src/__tests__/ConfigView.test.js
index 5c8dad1..a0cd825 100644
--- a/frontend/src/__tests__/ConfigView.test.js
+++ b/frontend/src/__tests__/ConfigView.test.js
@@ -181,6 +181,6 @@ describe('ConfigView.vue', () => {
 
     expect(wrapper.text()).toContain('应用版本号')
     expect(wrapper.text()).not.toContain('打包参数')
-    expect(wrapper.findAll('input').length).toBe(2)
+    expect(wrapper.findAll('input').length).toBe(1)
   })
 })
diff --git a/frontend/src/views/ConfigView.vue b/frontend/src/views/ConfigView.vue
index c10ce06..35052ae 100644
--- a/frontend/src/views/ConfigView.vue
+++ b/frontend/src/views/ConfigView.vue
@@ -273,11 +273,7 @@
               <input type="text" v-model="versions.app_ver" placeholder="2.180.0">
               <div style="font-size: 12px; color: #999; margin-top: 4px;">格式：主版本.次版本.修订号</div>
             </div>
-            <div class="form-group">
-              <label>Build_Ver（构建版本）</label>
-              <input type="text" v-model="versions.build_ver" placeholder="2.180.0.0">
-              <div style="font-size: 12px; color: #999; margin-top: 4px;">格式：主版本.次版本.修订号.构建号（App_Store 打包时构建号自动 +1）</div>
-            </div>
+            <div style="font-size: 12px; color: #999; margin: -8px 0 16px;">保存后 Build_Ver 将自动重置为 App_Ver.0；App Store 打包时构建号自动 +1。</div>
             <button class="btn btn-primary" style="width: auto; padding: 10px 32px; margin-bottom: 24px;" @click="saveVersions">保存版本号</button>
 
             <template v-if="isAdmin">
@@ -1037,7 +1033,7 @@ const saveVersions = async () => {
     const res = await authFetch('/api/config/versions', {
       method: 'PUT',
       headers: { 'Content-Type': 'application/json' },
-      body: JSON.stringify(versions.value),
+      body: JSON.stringify({ app_ver: versions.value.app_ver }),
     })
     if (res.ok) {
       const data = await res.json()
diff --git a/tests/test_api_config.py b/tests/test_api_config.py
index d7dbb49..ccfec86 100644
--- a/tests/test_api_config.py
+++ b/tests/test_api_config.py
@@ -144,3 +144,19 @@ def test_update_build_settings(client, tmp_config):
     resp = client.put("/api/config/build", json={"max_concurrent_builds": 4})
     assert resp.status_code == 200
     assert client.get("/api/config/build").json()["max_concurrent_builds"] == 4
+
+
+# ---- Versions ----
+
+def test_update_versions_resets_build_number(client, tmp_config):
+    resp = client.put("/api/config/versions", json={"app_ver": "2.196.0"})
+    assert resp.status_code == 200
+    assert resp.json()["app_ver"] == "2.196.0"
+    assert resp.json()["build_ver"] == "2.196.0.0"
+    assert client.get("/api/config/versions").json()["build_ver"] == "2.196.0.0"
+
+
+def test_update_versions_rejects_invalid_app_version(client, tmp_config):
+    resp = client.put("/api/config/versions", json={"app_ver": "2.196"})
+    assert resp.status_code == 400
+    assert "App_Ver" in resp.json()["detail"]
diff --git a/tests/test_security.py b/tests/test_security.py
index 0143e8c..32f2ca6 100644
--- a/tests/test_security.py
+++ b/tests/test_security.py
@@ -56,9 +56,9 @@ def test_config_routes_limit_regular_users_to_apps_and_versions(client, tmp_conf
     assert client.get("/api/config/apps", headers=headers).status_code == 200
     assert client.post("/api/config/apps", json={"name": "普通用户 App"}, headers=headers).status_code == 200
     assert client.get("/api/config/versions", headers=headers).status_code == 200
-    assert client.put("/api/config/versions", json={
-        "app_ver": "2.196.0", "build_ver": "2.196.0.0",
-    }, headers=headers).status_code == 200
+    versions = client.put("/api/config/versions", json={"app_ver": "2.196.0"}, headers=headers)
+    assert versions.status_code == 200
+    assert versions.json()["build_ver"] == "2.196.0.0"
     assert client.get("/api/config", headers=headers).status_code == 403
     assert client.get("/api/config/servers", headers=headers).status_code == 403
     assert client.put("/api/config/build", json={"max_concurrent_builds": 1}, headers=headers).status_code == 403