diff --git a/packages/date-picker/src/basic/date-table.vue b/packages/date-picker/src/basic/date-table.vue
index e4e3a8120..014500a2a 100644
--- a/packages/date-picker/src/basic/date-table.vue
+++ b/packages/date-picker/src/basic/date-table.vue
@@ -131,7 +131,7 @@
         const disabledDate = this.disabledDate;
         const now = clearHours(new Date());
 
-        for (var i = 0; i < 6; i++) {
+        for (let i = 0; i < 6; i++) {
           const row = rows[i];
 
           if (this.showWeekNumber) {
@@ -140,7 +140,7 @@
             }
           }
 
-          for (var j = 0; j < 7; j++) {
+          for (let j = 0; j < 7; j++) {
             let cell = row[this.showWeekNumber ? j + 1 : j];
             if (!cell) {
               cell = { row: i, column: j, type: 'normal', inRange: false, start: false, end: false };
@@ -455,7 +455,7 @@
         } else if (selectionMode === 'day') {
           this.$emit('pick', newDate);
         } else if (selectionMode === 'week') {
-          var weekNumber = getWeekNumber(newDate);
+          const weekNumber = getWeekNumber(newDate);
 
           const value = newDate.getFullYear() + 'w' + weekNumber;
           this.$emit('pick', {
diff --git a/packages/dropdown/src/dropdown.vue b/packages/dropdown/src/dropdown.vue
index 55b72702e..931f749a2 100644
--- a/packages/dropdown/src/dropdown.vue
+++ b/packages/dropdown/src/dropdown.vue
@@ -243,7 +243,7 @@
     render(h) {
       let { hide, splitButton, type, dropdownSize } = this;
 
-      var handleMainButtonClick = (event) => {
+      const handleMainButtonClick = (event) => {
         this.$emit('click', event);
         hide();
       };
diff --git a/packages/form/src/form-item.vue b/packages/form/src/form-item.vue
index 09a3e0671..f155174b3 100644
--- a/packages/form/src/form-item.vue
+++ b/packages/form/src/form-item.vue
@@ -89,20 +89,20 @@
         return this.for || this.prop;
       },
       labelStyle() {
-        var ret = {};
+        const ret = {};
         if (this.form.labelPosition === 'top') return ret;
-        var labelWidth = this.labelWidth || this.form.labelWidth;
+        const labelWidth = this.labelWidth || this.form.labelWidth;
         if (labelWidth) {
           ret.width = labelWidth;
         }
         return ret;
       },
       contentStyle() {
-        var ret = {};
+        const ret = {};
         const label = this.label;
         if (this.form.labelPosition === 'top' || this.form.inline) return ret;
         if (!label && !this.labelWidth && this.isNested) return ret;
-        var labelWidth = this.labelWidth || this.form.labelWidth;
+        const labelWidth = this.labelWidth || this.form.labelWidth;
         if (labelWidth) {
           ret.marginLeft = labelWidth;
         }
@@ -123,10 +123,10 @@
       fieldValue: {
         cache: false,
         get() {
-          var model = this.form.model;
+          const model = this.form.model;
           if (!model || !this.prop) { return; }
 
-          var path = this.prop;
+          let path = this.prop;
           if (path.indexOf(':') !== -1) {
             path = path.replace(/:/, '.');
           }
@@ -171,7 +171,7 @@
     methods: {
       validate(trigger, callback = noop) {
         this.validateDisabled = false;
-        var rules = this.getFilteredRule(trigger);
+        const rules = this.getFilteredRule(trigger);
         if ((!rules || rules.length === 0) && this.required === undefined) {
           callback();
           return true;
@@ -179,7 +179,7 @@
 
         this.validateState = 'validating';
 
-        var descriptor = {};
+        const descriptor = {};
         if (rules && rules.length > 0) {
           rules.forEach(rule => {
             delete rule.trigger;
@@ -187,8 +187,8 @@
         }
         descriptor[this.prop] = rules;
 
-        var validator = new AsyncValidator(descriptor);
-        var model = {};
+        const validator = new AsyncValidator(descriptor);
+        const model = {};
 
         model[this.prop] = this.fieldValue;
 
@@ -226,16 +226,16 @@
         }
       },
       getRules() {
-        var formRules = this.form.rules;
-        var selfRules = this.rules;
-        var requiredRule = this.required !== undefined ? { required: !!this.required } : [];
+        let formRules = this.form.rules;
+        const selfRules = this.rules;
+        const requiredRule = this.required !== undefined ? { required: !!this.required } : [];
 
         formRules = formRules ? getPropByPath(formRules, this.prop || '').o[this.prop || ''] : [];
 
         return [].concat(selfRules || formRules || []).concat(requiredRule);
       },
       getFilteredRule(trigger) {
-        var rules = this.getRules();
+        const rules = this.getRules();
 
         return rules.filter(rule => {
           return !rule.trigger || rule.trigger.indexOf(trigger) !== -1;
diff --git a/packages/input/src/input.vue b/packages/input/src/input.vue
index 2ac7e3b1f..9c1796344 100644
--- a/packages/input/src/input.vue
+++ b/packages/input/src/input.vue
@@ -234,7 +234,7 @@
       },
       resizeTextarea() {
         if (this.$isServer) return;
-        var { autosize, type } = this;
+        const { autosize, type } = this;
         if (type !== 'textarea') return;
         if (!autosize) {
           this.textareaCalcStyle = {
diff --git a/packages/message-box/src/main.vue b/packages/message-box/src/main.vue
index 8d25e1ad2..4eb29e7a1 100644
--- a/packages/message-box/src/main.vue
+++ b/packages/message-box/src/main.vue
@@ -213,15 +213,15 @@
 
       validate() {
         if (this.$type === 'prompt') {
-          var inputPattern = this.inputPattern;
+          const inputPattern = this.inputPattern;
           if (inputPattern && !inputPattern.test(this.inputValue || '')) {
             this.editorErrorMessage = this.inputErrorMessage || t('el.messagebox.error');
             addClass(this.getInputElement(), 'invalid');
             return false;
           }
-          var inputValidator = this.inputValidator;
+          const inputValidator = this.inputValidator;
           if (typeof inputValidator === 'function') {
-            var validateResult = inputValidator(this.inputValue);
+            const validateResult = inputValidator(this.inputValue);
             if (validateResult === false) {
               this.editorErrorMessage = this.inputErrorMessage || t('el.messagebox.error');
               addClass(this.getInputElement(), 'invalid');
diff --git a/packages/progress/src/progress.vue b/packages/progress/src/progress.vue
index b1c733e10..718222cc3 100644
--- a/packages/progress/src/progress.vue
+++ b/packages/progress/src/progress.vue
@@ -74,7 +74,7 @@
     },
     computed: {
       barStyle() {
-        var style = {};
+        const style = {};
         style.width = this.percentage + '%';
         return style;
       },
@@ -82,16 +82,16 @@
         return (this.strokeWidth / this.width * 100).toFixed(1);
       },
       trackPath() {
-        var radius = parseInt(50 - parseFloat(this.relativeStrokeWidth) / 2, 10);
+        const radius = parseInt(50 - parseFloat(this.relativeStrokeWidth) / 2, 10);
 
         return `M 50 50 m 0 -${radius} a ${radius} ${radius} 0 1 1 0 ${radius * 2} a ${radius} ${radius} 0 1 1 0 -${radius * 2}`;
       },
       perimeter() {
-        var radius = 50 - parseFloat(this.relativeStrokeWidth) / 2;
+        const radius = 50 - parseFloat(this.relativeStrokeWidth) / 2;
         return 2 * Math.PI * radius;
       },
       circlePathStyle() {
-        var perimeter = this.perimeter;
+        const perimeter = this.perimeter;
         return {
           strokeDasharray: `${perimeter}px,${perimeter}px`,
           strokeDashoffset: (1 - this.percentage / 100) * perimeter + 'px',
@@ -99,7 +99,7 @@
         };
       },
       stroke() {
-        var ret;
+        let ret;
         switch (this.status) {
           case 'success':
             ret = '#13ce66';
diff --git a/packages/row/src/row.js b/packages/row/src/row.js
index fb3ba0640..5611d7ce9 100644
--- a/packages/row/src/row.js
+++ b/packages/row/src/row.js
@@ -22,7 +22,7 @@ export default {
 
   computed: {
     style() {
-      var ret = {};
+      const ret = {};
 
       if (this.gutter) {
         ret.marginLeft = `-${this.gutter / 2}px`;
diff --git a/packages/upload/src/iframe-upload.vue b/packages/upload/src/iframe-upload.vue
index 48d8b1a6b..88dec6fb7 100644
--- a/packages/upload/src/iframe-upload.vue
+++ b/packages/upload/src/iframe-upload.vue
@@ -105,9 +105,9 @@ export default {
     const self = this;
     !this.$isServer && window.addEventListener('message', (event) => {
       if (!self.file) return;
-      var targetOrigin = new URL(self.action).origin;
+      const targetOrigin = new URL(self.action).origin;
       if (event.origin !== targetOrigin) return;
-      var response = event.data;
+      const response = event.data;
       if (response.result === 'success') {
         self.onSuccess(response, self.file);
       } else if (response.result === 'failed') {