diff --git a/src/count-down/__test__/__snapshots__/demo.test.jsx.snap b/src/count-down/__test__/__snapshots__/demo.test.jsx.snap
index ad69e8506..2269084d3 100644
--- a/src/count-down/__test__/__snapshots__/demo.test.jsx.snap
+++ b/src/count-down/__test__/__snapshots__/demo.test.jsx.snap
@@ -17,7 +17,7 @@ exports[`CountDown > CountDown baseVue demo works fine 1`] = `
       class="demo-count-down-content"
     >
       <div
-        class="t-count-down t-count-down--default t-count-down--small"
+        class="t-count-down t-count-down--default t-count-down--medium"
       >
         
         
@@ -68,7 +68,7 @@ exports[`CountDown > CountDown baseVue demo works fine 1`] = `
       class="demo-count-down-content"
     >
       <div
-        class="t-count-down t-count-down--default t-count-down--small"
+        class="t-count-down t-count-down--default t-count-down--medium"
       >
         
         
@@ -131,7 +131,7 @@ exports[`CountDown > CountDown baseVue demo works fine 1`] = `
       class="demo-count-down-content"
     >
       <div
-        class="t-count-down t-count-down--square t-count-down--small"
+        class="t-count-down t-count-down--square t-count-down--medium"
       >
         
         
@@ -182,7 +182,7 @@ exports[`CountDown > CountDown baseVue demo works fine 1`] = `
       class="demo-count-down-content"
     >
       <div
-        class="t-count-down t-count-down--round t-count-down--small"
+        class="t-count-down t-count-down--round t-count-down--medium"
       >
         
         
@@ -233,7 +233,7 @@ exports[`CountDown > CountDown baseVue demo works fine 1`] = `
       class="demo-count-down-content"
     >
       <div
-        class="t-count-down t-count-down--round t-count-down--small"
+        class="t-count-down t-count-down--round t-count-down--medium"
       >
         
         
@@ -288,7 +288,7 @@ exports[`CountDown > CountDown baseVue demo works fine 1`] = `
       class="demo-count-down-content"
     >
       <div
-        class="t-count-down t-count-down--default t-count-down--small custom"
+        class="t-count-down t-count-down--default t-count-down--medium custom"
       >
         
         
@@ -383,7 +383,7 @@ exports[`CountDown > CountDown mobileVue demo works fine 1`] = `
           class="demo-count-down-content"
         >
           <div
-            class="t-count-down t-count-down--default t-count-down--small"
+            class="t-count-down t-count-down--default t-count-down--medium"
           >
             
             
@@ -434,7 +434,7 @@ exports[`CountDown > CountDown mobileVue demo works fine 1`] = `
           class="demo-count-down-content"
         >
           <div
-            class="t-count-down t-count-down--default t-count-down--small"
+            class="t-count-down t-count-down--default t-count-down--medium"
           >
             
             
@@ -497,7 +497,7 @@ exports[`CountDown > CountDown mobileVue demo works fine 1`] = `
           class="demo-count-down-content"
         >
           <div
-            class="t-count-down t-count-down--square t-count-down--small"
+            class="t-count-down t-count-down--square t-count-down--medium"
           >
             
             
@@ -548,7 +548,7 @@ exports[`CountDown > CountDown mobileVue demo works fine 1`] = `
           class="demo-count-down-content"
         >
           <div
-            class="t-count-down t-count-down--round t-count-down--small"
+            class="t-count-down t-count-down--round t-count-down--medium"
           >
             
             
@@ -599,7 +599,7 @@ exports[`CountDown > CountDown mobileVue demo works fine 1`] = `
           class="demo-count-down-content"
         >
           <div
-            class="t-count-down t-count-down--round t-count-down--small"
+            class="t-count-down t-count-down--round t-count-down--medium"
           >
             
             
@@ -654,7 +654,7 @@ exports[`CountDown > CountDown mobileVue demo works fine 1`] = `
           class="demo-count-down-content"
         >
           <div
-            class="t-count-down t-count-down--default t-count-down--small custom"
+            class="t-count-down t-count-down--default t-count-down--medium custom"
           >
             
             
@@ -778,7 +778,7 @@ exports[`CountDown > CountDown mobileVue demo works fine 1`] = `
           class="demo-count-down-content"
         >
           <div
-            class="t-count-down t-count-down--default t-count-down--small"
+            class="t-count-down t-count-down--default t-count-down--medium"
           >
             
             
@@ -925,7 +925,7 @@ exports[`CountDown > CountDown mobileVue demo works fine 1`] = `
           class="demo-count-down-content"
         >
           <div
-            class="t-count-down t-count-down--default t-count-down--small"
+            class="t-count-down t-count-down--default t-count-down--medium"
           >
             
             
@@ -1084,7 +1084,7 @@ exports[`CountDown > CountDown mobileVue demo works fine 1`] = `
           class="demo-count-down-content"
         >
           <div
-            class="t-count-down t-count-down--square t-count-down--small"
+            class="t-count-down t-count-down--square t-count-down--medium"
           >
             
             
@@ -1219,7 +1219,7 @@ exports[`CountDown > CountDown mobileVue demo works fine 1`] = `
           class="demo-count-down-content"
         >
           <div
-            class="t-count-down t-count-down--round t-count-down--small"
+            class="t-count-down t-count-down--round t-count-down--medium"
           >
             
             
@@ -1358,7 +1358,7 @@ exports[`CountDown > CountDown mobileVue demo works fine 1`] = `
           class="demo-count-down-content"
         >
           <div
-            class="t-count-down t-count-down--round t-count-down--small"
+            class="t-count-down t-count-down--round t-count-down--medium"
           >
             
             
@@ -1513,7 +1513,7 @@ exports[`CountDown > CountDown sizeVue demo works fine 1`] = `
       class="demo-count-down-content"
     >
       <div
-        class="t-count-down t-count-down--default t-count-down--small"
+        class="t-count-down t-count-down--default t-count-down--medium"
       >
         
         
@@ -1660,7 +1660,7 @@ exports[`CountDown > CountDown sizeVue demo works fine 1`] = `
       class="demo-count-down-content"
     >
       <div
-        class="t-count-down t-count-down--default t-count-down--small"
+        class="t-count-down t-count-down--default t-count-down--medium"
       >
         
         
@@ -1819,7 +1819,7 @@ exports[`CountDown > CountDown sizeVue demo works fine 1`] = `
       class="demo-count-down-content"
     >
       <div
-        class="t-count-down t-count-down--square t-count-down--small"
+        class="t-count-down t-count-down--square t-count-down--medium"
       >
         
         
@@ -1954,7 +1954,7 @@ exports[`CountDown > CountDown sizeVue demo works fine 1`] = `
       class="demo-count-down-content"
     >
       <div
-        class="t-count-down t-count-down--round t-count-down--small"
+        class="t-count-down t-count-down--round t-count-down--medium"
       >
         
         
@@ -2093,7 +2093,7 @@ exports[`CountDown > CountDown sizeVue demo works fine 1`] = `
       class="demo-count-down-content"
     >
       <div
-        class="t-count-down t-count-down--round t-count-down--small"
+        class="t-count-down t-count-down--round t-count-down--medium"
       >
         
         
diff --git a/src/count-down/__test__/index.test.jsx b/src/count-down/__test__/index.test.jsx
index 530789589..cd0b5a4ea 100644
--- a/src/count-down/__test__/index.test.jsx
+++ b/src/count-down/__test__/index.test.jsx
@@ -60,7 +60,7 @@ describe('countdown.vue', async () => {
 
     it('size', async () => {
       const wrapper = mount(<CountDown time={100000}></CountDown>);
-      expect(wrapper.find('.t-count-down--small').exists()).toBe(true);
+      expect(wrapper.find('.t-count-down--medium').exists()).toBe(true);
     });
 
     it('theme', async () => {
diff --git a/src/count-down/count-down.md b/src/count-down/count-down.md
index 6efea1346..a50f27d42 100644
--- a/src/count-down/count-down.md
+++ b/src/count-down/count-down.md
@@ -9,7 +9,7 @@ autoStart | Boolean | true | 是否自动开始倒计时 | N
 content | String / Slot / Function | 'default' | 最终倒计时的展示内容，值为'default'时使用默认的格式，否则使用自定义样式插槽。TS 类型：`string \| TNode`。[通用类型定义](https://github.com/Tencent/tdesign-mobile-vue/blob/develop/src/common.ts) | N
 format | String | HH:mm:ss | 时间格式，DD-日，HH-时，mm-分，ss-秒，SSS-毫秒 | N
 millisecond | Boolean | false | 是否开启毫秒级渲染 | N
-size | String | 'small' | 倒计时尺寸。可选项：small/medium/large | N
+size | String | 'medium' | 倒计时尺寸。可选项：small/medium/large | N
 splitWithUnit | Boolean | false | 使用时间单位分割 | N
 theme | String | 'default' | 倒计时风格。可选项：default/round/square | N
 time | Number | - | 必需。倒计时时长，单位毫秒 | Y
diff --git a/src/count-down/props.ts b/src/count-down/props.ts
index a0c0b917f..396716ed1 100644
--- a/src/count-down/props.ts
+++ b/src/count-down/props.ts
@@ -28,7 +28,7 @@ export default {
   /** 倒计时尺寸 */
   size: {
     type: String as PropType<TdCountDownProps['size']>,
-    default: 'small' as TdCountDownProps['size'],
+    default: 'medium' as TdCountDownProps['size'],
     validator(val: TdCountDownProps['size']): boolean {
       if (!val) return true;
       return ['small', 'medium', 'large'].includes(val);