diff --git a/packages/core/src/services/model/manager.ts b/packages/core/src/services/model/manager.ts
index ccef7978..afdcaec0 100644
--- a/packages/core/src/services/model/manager.ts
+++ b/packages/core/src/services/model/manager.ts
@@ -332,11 +332,11 @@ export class ModelManager implements IModelManager {
             ...existingTextModelConfig.connectionConfig,
             ...(config.connectionConfig || {})
           },
-          // Deep merge paramOverrides
-          paramOverrides: {
-            ...existingTextModelConfig.paramOverrides,
-            ...(config.paramOverrides || {})
-          }
+          // 处理 paramOverrides：如果明确传入了 paramOverrides，则直接替换而不是合并
+          // 这样可以确保用户删除的参数不会被错误地保留
+          paramOverrides: config.paramOverrides !== undefined
+            ? config.paramOverrides
+            : existingTextModelConfig.paramOverrides || {}
         };
 
         // 如果更新了关键字段，需要验证配置
diff --git a/packages/ui/src/components/TextModelEditModal.vue b/packages/ui/src/components/TextModelEditModal.vue
index a0c7af18..51092122 100644
--- a/packages/ui/src/components/TextModelEditModal.vue
+++ b/packages/ui/src/components/TextModelEditModal.vue
@@ -331,7 +331,7 @@
 </template>
 
 <script setup lang="ts">
-import { computed, inject } from 'vue'
+import { computed, inject, nextTick } from 'vue'
 import { useI18n } from 'vue-i18n'
 import {
   NModal,
@@ -403,11 +403,15 @@ const isSaving = manager.isSaving
 
 const isEditing = computed(() => !!manager.editingModelId.value)
 
-const handleUpdateShow = (value: boolean) => {
+const handleUpdateShow = async (value: boolean) => {
+  emit('update:show', value)
+
+  // 只有在明确关闭时才重置表单状态
   if (!value) {
+    // 等待父组件处理状态变化后再重置表单
+    await nextTick()
     manager.resetFormState()
   }
-  emit('update:show', value)
 }
 
 const handleSubmit = async () => {
diff --git a/packages/ui/src/components/TextModelManager.vue b/packages/ui/src/components/TextModelManager.vue
index 8758377f..8f5a2376 100644
--- a/packages/ui/src/components/TextModelManager.vue
+++ b/packages/ui/src/components/TextModelManager.vue
@@ -41,6 +41,11 @@ const handleModelUpdated = async (id?: string) => {
   if (targetId) {
     emit('modelsUpdated', targetId)
   }
+
+  // 保存成功后关闭模态框并重置表单状态
+  showEditModal.value = false
+  editingModelId.value = null
+  manager.resetFormState()
 }
 
 const handleTestConnection = async (id: string) => {
@@ -48,16 +53,27 @@ const handleTestConnection = async (id: string) => {
 }
 
 const handleEditModel = async (id: string) => {
-  await manager.prepareForEdit(id)
+  // 如果已经在编辑同一个模型且模态框已经打开，直接返回
+  if (editingModelId.value === id && showEditModal.value === true) {
+    return
+  }
+
+  // 如果切换到不同的模型，重置表单状态
+  if (editingModelId.value && editingModelId.value !== id) {
+    manager.resetFormState()
+  }
+
+  // 准备编辑模式（总是会执行，因为我们需要确保状态正确）
+  await manager.prepareForEdit(id, true)
   editingModelId.value = id
   showEditModal.value = true
 }
 
 const updateEditModalVisibility = (value: boolean) => {
   showEditModal.value = value
+  // 当模态框关闭时，重置编辑状态但不重置表单数据
   if (!value) {
     editingModelId.value = null
-    manager.resetFormState()
   }
 }
 
diff --git a/packages/ui/src/composables/useTextModelManager.ts b/packages/ui/src/composables/useTextModelManager.ts
index 601a970a..6db8a813 100644
--- a/packages/ui/src/composables/useTextModelManager.ts
+++ b/packages/ui/src/composables/useTextModelManager.ts
@@ -139,7 +139,18 @@ export function useTextModelManager() {
     )
   })
 
-  const canTestFormConnection = computed(() => !!editingModelId.value && !isTestingFormConnection.value)
+  const canTestFormConnection = computed(() => {
+    // 必须在编辑模式下
+    if (!editingModelId.value) return false
+    // 测试期间禁用
+    if (isTestingFormConnection.value) return false
+    // 必须有必需的连接配置
+    if (!isConnectionConfigured.value) return false
+    // 必须有模型名称
+    if (!form.value.name?.trim()) return false
+
+    return true
+  })
   const canRefreshModelOptions = computed(() => {
     return selectedProvider.value?.supportsDynamicModels && isConnectionConfigured.value && !isLoadingModelOptions.value
   })
@@ -334,7 +345,12 @@ export function useTextModelManager() {
     formReady.value = true
   }
 
-  const prepareForEdit = async (id: string) => {
+  const prepareForEdit = async (id: string, forceReload = true) => {
+    // 如果已经在编辑同一个模型且不强制重新加载，则跳过
+    if (!forceReload && editingModelId.value === id && formReady.value) {
+      return
+    }
+
     resetFormState()
     editingModelId.value = id
     await ensureProvidersLoaded()
@@ -546,13 +562,56 @@ export function useTextModelManager() {
   }
 
   const testFormConnection = async () => {
-    if (!editingModelId.value || isTestingFormConnection.value) return
+    // 使用 canTestFormConnection 的完整校验逻辑
+    if (!canTestFormConnection.value) return
+
     isTestingFormConnection.value = true
     formConnectionStatus.value = { type: 'info', message: t('modelManager.testing') }
+
     try {
-      await llmService.testConnection(editingModelId.value)
-      formConnectionStatus.value = { type: 'success', message: t('modelManager.testSuccess', { provider: form.value.name }) }
-      toast.success(t('modelManager.testSuccess', { provider: form.value.name }))
+      // 获取原始配置
+      const existingConfig = await modelManager.getModel(editingModelId.value)
+      if (!existingConfig) {
+        throw new Error('模型配置不存在')
+      }
+
+      // 创建临时测试配置，使用当前表单的参数覆盖
+      // 注意：如果 API Key 被脱敏显示，需要使用原始 Key
+      const connectionConfig = {
+        ...form.value.connectionConfig,
+        apiKey: form.value.displayMaskedKey && form.value.originalApiKey
+          ? form.value.originalApiKey
+          : form.value.connectionConfig.apiKey
+      }
+
+      const tempConfig: TextModelConfig = {
+        ...existingConfig,
+        id: `temp-test-${editingModelId.value}`,
+        name: form.value.name,
+        enabled: form.value.enabled,
+        providerMeta: { ...existingConfig.providerMeta },
+        modelMeta: { ...existingConfig.modelMeta },
+        connectionConfig,
+        paramOverrides: { ...(form.value.paramOverrides || {}) }
+      }
+
+      // 创建临时模型用于测试
+      await modelManager.addModel(tempConfig.id, tempConfig)
+
+      try {
+        // 测试临时模型
+        await llmService.testConnection(tempConfig.id)
+        formConnectionStatus.value = { type: 'success', message: t('modelManager.testSuccess', { provider: form.value.name }) }
+        toast.success(t('modelManager.testSuccess', { provider: form.value.name }))
+      } finally {
+        // 清理临时模型
+        try {
+          await modelManager.deleteModel(tempConfig.id)
+        } catch (cleanupError) {
+          console.warn('清理临时测试模型失败:', cleanupError)
+        }
+      }
+
     } catch (error: any) {
       console.error('连接测试失败:', error)
       formConnectionStatus.value = {