diff --git a/package.json b/package.json
index 1ed6313..6bcad3a 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
     "name": "shrimp-admin",
-    "version": "0.3.7",
+    "version": "0.3.8",
     "private": true,
     "description": "Shrimp 框架前端 — 消费 ShrimpServer + ShrimpTable 契约的经典 Vue3 + Element Plus 实现",
     "main": "src/index.ts",
diff --git a/src/components/ShrimpTable.vue b/src/components/ShrimpTable.vue
index 0e88e16..d3701e5 100644
--- a/src/components/ShrimpTable.vue
+++ b/src/components/ShrimpTable.vue
@@ -334,8 +334,10 @@ async function handleSave() {
             formFields.value.forEach(field => {
                 if (field.editable === 'readonly') return
                 if (field.editable === 'addOnly') return
-                const newValue = formData.value[field.key]
-                const oldValue = originalData.value[field.key]
+                // 清空字段值为 undefined 时，JSON.stringify 会丢键 → 后端收不到、看似"提交无效"。
+                // 归一成 null：既保证清空能提交(后端置空)，又让"两边都空"不误判为有改动。
+                const newValue = formData.value[field.key] ?? null
+                const oldValue = originalData.value[field.key] ?? null
                 if (newValue === oldValue) return
                 submitData[field.key] = newValue
             })
diff --git a/src/components/fields/FieldRelation.vue b/src/components/fields/FieldRelation.vue
index b86613e..be5fed4 100644
--- a/src/components/fields/FieldRelation.vue
+++ b/src/components/fields/FieldRelation.vue
@@ -39,9 +39,10 @@ const emit = defineEmits<{
     'update:modelValue': [value: any]
 }>()
 
-// 编辑态清空：el-select 单选清空发 ''，但 relation 是 ObjectId，存 '' 会 cast 报错 → 归一成 null(取消关联)
+// 编辑态清空：el-select 单选清空发 '' 或 undefined，relation 是 ObjectId、且 undefined 会被
+// JSON.stringify 丢键 → 都归一成 null(取消关联)。多选清空是 []，原样。
 function onEdit(v: any) {
-    emit('update:modelValue', v === '' ? null : v)
+    emit('update:modelValue', v === '' || v == null ? (props.field.multiple ? [] : null) : v)
 }
 
 const options = ref<{ label: string; value: string }[]>([])