diff --git a/packages/editor/src/layouts/history-list/BucketTab.vue b/packages/editor/src/layouts/history-list/BucketTab.vue
index e09f4e0d..7470d749 100644
--- a/packages/editor/src/layouts/history-list/BucketTab.vue
+++ b/packages/editor/src/layouts/history-list/BucketTab.vue
@@ -1,7 +1,7 @@
 <template>
   <div v-if="!buckets.length" class="m-editor-history-list-empty">暂无操作记录</div>
   <template v-else>
-    <div class="m-editor-history-list-toolbar">
+    <div v-if="config.showClear !== false" class="m-editor-history-list-toolbar">
       <span class="m-editor-history-list-clear" :title="`清空${config.title}的历史记录`" @click="$emit('clear')"
         >清空</span
       >
@@ -38,7 +38,7 @@ defineOptions({
 
 defineProps<{
   /**
-   * 该类历史的整体渲染配置（title / prefix / describe* / isStep* / showInitial / gotoEnabled），
+   * 该类历史的整体渲染配置（title / prefix / describe* / isStep* / showInitial / gotoEnabled / showClear），
    * 由父组件按业务类型注入并整体透传给 Bucket，避免逐项透传多个 props。
    */
   config: HistoryBucketConfig<T>;
diff --git a/packages/editor/src/layouts/history-list/HistoryDiffDialog.vue b/packages/editor/src/layouts/history-list/HistoryDiffDialog.vue
index 041ad6b0..a2f3d5e6 100644
--- a/packages/editor/src/layouts/history-list/HistoryDiffDialog.vue
+++ b/packages/editor/src/layouts/history-list/HistoryDiffDialog.vue
@@ -21,7 +21,7 @@
           </TMagicRadioGroup>
 
           <TMagicRadioGroup v-model="mode" size="small" class="m-editor-history-diff-dialog-mode">
-            <TMagicRadioButton value="before">与修改前对比</TMagicRadioButton>
+            <TMagicRadioButton value="before" :disabled="!hasValue">与修改前对比</TMagicRadioButton>
             <TMagicRadioButton value="current" :disabled="!hasCurrent">与当前对比</TMagicRadioButton>
           </TMagicRadioGroup>
         </div>
@@ -159,6 +159,15 @@ const dialogTitle = computed(() => (props.onConfirm ? '确认回滚' : '查看
 
 const hasCurrent = computed(() => payload.value?.currentValue !== undefined && payload.value?.currentValue !== null);
 
+/** 是否存在该步「修改后的值」：不存在（如仅删除）时「与修改前对比」无意义，置灰禁用。 */
+const hasValue = computed(() => payload.value?.value !== undefined && payload.value?.value !== null);
+
+/**
+ * 计算 open 时的初始对比模式：
+ * 没有「修改后的值」但有当前值时（「与修改前对比」不可用），默认进入「与当前对比」；否则默认「与修改前对比」。
+ */
+const resolveInitialMode = (): DiffMode => (!hasValue.value && hasCurrent.value ? 'current' : 'before');
+
 /** 左侧（旧/参照）值 */
 const leftValue = computed<Record<string, any>>(() => {
   if (!payload.value) return {};
@@ -212,8 +221,9 @@ const targetText = computed(() => {
 
 const open = (p: DiffDialogPayload) => {
   payload.value = p;
-  // 每次打开按需重置默认模式：有当前值时优先「与当前对比」更贴近"看现在差什么"，否则回退到默认
-  mode.value = 'before';
+  // 每次打开按 payload 重置对比模式（hasValue / hasCurrent 依赖 payload，需先赋值）：
+  // 无「修改后的值」但有当前值时默认「与当前对比」，否则默认「与修改前对比」
+  mode.value = resolveInitialMode();
   // 默认回到表单对比形态，避免残留上一次选择的源码模式
   viewMode.value = 'form';
   visible.value = true;
diff --git a/packages/editor/src/type.ts b/packages/editor/src/type.ts
index 4abc1314..45d19285 100644
--- a/packages/editor/src/type.ts
+++ b/packages/editor/src/type.ts
@@ -1353,6 +1353,8 @@ export interface HistoryBucketConfig<T extends BaseStepValue = BaseStepValue> ex
   showInitial?: boolean;
   /** 是否支持「跳转到该记录」(goto)，默认 true。 */
   gotoEnabled?: boolean;
+  /** 是否展示顶部「清空」按钮，默认 true。无需提供清空能力的自定义历史可传 false。 */
+  showClear?: boolean;
 }
 
 export interface UseHistoryRevertOptions {
diff --git a/packages/editor/tests/unit/layouts/history-list/BucketTab.spec.ts b/packages/editor/tests/unit/layouts/history-list/BucketTab.spec.ts
index 64a9591b..7af19eae 100644
--- a/packages/editor/tests/unit/layouts/history-list/BucketTab.spec.ts
+++ b/packages/editor/tests/unit/layouts/history-list/BucketTab.spec.ts
@@ -16,7 +16,7 @@ const buildConfig = (): HistoryBucketConfig<any> => ({
   describeStep: () => 'sub-desc',
 });
 
-const buildGroup = () => ({
+const buildGroup = (): any => ({
   applied: true,
   opType: 'update' as const,
   steps: [{ index: 0, applied: true, step: { mark: 's-0' } }],
@@ -58,6 +58,18 @@ describe('BucketTab.vue', () => {
     expect(wrapper.emitted('clear')).toBeTruthy();
   });
 
+  test('config.showClear 为 false 时不渲染清空按钮', () => {
+    const wrapper = mount(BucketTab, {
+      props: {
+        config: { ...buildConfig(), showClear: false },
+        buckets: [{ id: 'ds_1', groups: [buildGroup()] }],
+        expanded: {},
+      },
+    });
+    expect(wrapper.find('.m-editor-history-list-toolbar').exists()).toBe(false);
+    expect(wrapper.find('.m-editor-history-list-clear').exists()).toBe(false);
+  });
+
   test('透传 Bucket 子组件事件', async () => {
     const wrapper = mount(BucketTab, {
       props: {
diff --git a/packages/editor/tests/unit/layouts/history-list/HistoryDiffDialog.spec.ts b/packages/editor/tests/unit/layouts/history-list/HistoryDiffDialog.spec.ts
index 436de10f..0ee8aa86 100644
--- a/packages/editor/tests/unit/layouts/history-list/HistoryDiffDialog.spec.ts
+++ b/packages/editor/tests/unit/layouts/history-list/HistoryDiffDialog.spec.ts
@@ -166,6 +166,43 @@ describe('HistoryDiffDialog.vue', () => {
     expect(currentRadio!.attributes('data-disabled')).toBe('true');
   });
 
+  test('无「修改后的值」时「与修改前对比」按钮置灰', async () => {
+    const wrapper = factory();
+    (wrapper.vm as any).open(basePayload({ value: null }));
+    await nextTick();
+
+    const beforeRadio = wrapper.findAll('.fake-radio-btn').find((b) => b.attributes('data-value') === 'before');
+    expect(beforeRadio!.attributes('data-disabled')).toBe('true');
+  });
+
+  test('无「修改后的值」但有当前值时默认进入「与当前对比」', async () => {
+    const wrapper = factory();
+    (wrapper.vm as any).open(basePayload({ value: null }));
+    await nextTick();
+
+    const form = wrapper.findComponent({ name: 'CompareForm' });
+    // current 模式：左=该步修改后 value（此处为空），右=当前 currentValue
+    expect(form.props('value')).toEqual({ text: 'current' });
+  });
+
+  test('无「修改后的值」且无当前值时仍默认「与修改前对比」', async () => {
+    const wrapper = factory();
+    (wrapper.vm as any).open(basePayload({ value: null, currentValue: null }));
+    await nextTick();
+
+    const form = wrapper.findComponent({ name: 'CompareForm' });
+    expect(form.props('lastValue')).toEqual({ text: 'old' });
+  });
+
+  test('有「修改后的值」时「与修改前对比」按钮可用', async () => {
+    const wrapper = factory();
+    (wrapper.vm as any).open(basePayload());
+    await nextTick();
+
+    const beforeRadio = wrapper.findAll('.fake-radio-btn').find((b) => b.attributes('data-value') === 'before');
+    expect(beforeRadio!.attributes('data-disabled')).toBe('false');
+  });
+
   test('targetText 按 category 生成前缀', async () => {
     const wrapper = factory();
     (wrapper.vm as any).open(basePayload({ category: 'data-source', targetLabel: '接口A' }));