diff --git a/src/datetime-picker/index.js b/src/datetime-picker/index.js
index a67449c68..3a468b06d 100644
--- a/src/datetime-picker/index.js
+++ b/src/datetime-picker/index.js
@@ -1,9 +1,10 @@
 import { createNamespace } from '../utils';
 import { range } from '../utils/format/number';
+import { isDate } from '../utils/validate/date';
 import { padZero } from '../utils/format/string';
 import Picker from '../picker';
 import { pickerProps } from '../picker/shared';
-import { times, isValidDate, getTrueValue, getMonthEndDay } from './utils';
+import { times, getTrueValue, getMonthEndDay } from './utils';
 
 const [createComponent, bem] = createNamespace('datetime-picker');
 const currentYear = new Date().getFullYear();
@@ -40,12 +41,12 @@ export default createComponent({
     minDate: {
       type: Date,
       default: () => new Date(currentYear - 10, 0, 1),
-      validator: isValidDate
+      validator: isDate
     },
     maxDate: {
       type: Date,
       default: () => new Date(currentYear + 10, 11, 31),
-      validator: isValidDate
+      validator: isDate
     },
     maxHour: {
       type: Number,
@@ -66,6 +67,7 @@ export default createComponent({
   watch: {
     value(val) {
       val = this.correctValue(val);
+
       const isEqual =
         this.type === 'time'
           ? val === this.innerValue
@@ -176,7 +178,7 @@ export default createComponent({
       // validate value
       const isDateType = this.type !== 'time';
 
-      if (isDateType && !isValidDate(value)) {
+      if (isDateType && !isDate(value)) {
         value = this.minDate;
       } else if (!value) {
         value = `${padZero(this.minHour)}:00`;
@@ -253,8 +255,8 @@ export default createComponent({
         const year = getTrueValue(values[0]);
         const month = getTrueValue(values[1]);
         const maxDate = getMonthEndDay(year, month);
-        let date = getTrueValue(values[2]);
 
+        let date = getTrueValue(values[2]);
         if (this.type === 'year-month') {
           date = 1;
         }
diff --git a/src/datetime-picker/utils.js b/src/datetime-picker/utils.js
deleted file mode 100644
index c54549e24..000000000
--- a/src/datetime-picker/utils.js
+++ /dev/null
@@ -1,25 +0,0 @@
-export function isValidDate(date) {
-  return Object.prototype.toString.call(date) === '[object Date]' && !isNaN(date.getTime());
-}
-
-export function times(n, iteratee) {
-  let index = -1;
-  const result = Array(n);
-
-  while (++index < n) {
-    result[index] = iteratee(index);
-  }
-  return result;
-}
-
-export function getTrueValue(formattedValue) {
-  if (!formattedValue) return;
-  while (isNaN(parseInt(formattedValue, 10))) {
-    formattedValue = formattedValue.slice(1);
-  }
-  return parseInt(formattedValue, 10);
-}
-
-export function getMonthEndDay(year, month) {
-  return 32 - new Date(year, month - 1, 32).getDate();
-}
diff --git a/src/datetime-picker/utils.ts b/src/datetime-picker/utils.ts
new file mode 100644
index 000000000..00006820d
--- /dev/null
+++ b/src/datetime-picker/utils.ts
@@ -0,0 +1,28 @@
+import { isNaN } from '../utils/validate/number';
+
+export function times(n: number, iteratee: (index: number) => any[]) {
+  let index = -1;
+  const result = Array(n);
+
+  while (++index < n) {
+    result[index] = iteratee(index);
+  }
+
+  return result;
+}
+
+export function getTrueValue(value: string | undefined): number | undefined {
+  if (!value) {
+    return;
+  }
+
+  while (isNaN(parseInt(value, 10))) {
+    value = value.slice(1);
+  }
+
+  return parseInt(value, 10);
+}
+
+export function getMonthEndDay(year: number, month: number): number {
+  return 32 - new Date(year, month - 1, 32).getDate();
+}
diff --git a/src/utils/validate/date.ts b/src/utils/validate/date.ts
new file mode 100644
index 000000000..f7a2e2ed1
--- /dev/null
+++ b/src/utils/validate/date.ts
@@ -0,0 +1,7 @@
+import { isNaN } from './number';
+
+export function isDate(date: Date): boolean {
+  return (
+    Object.prototype.toString.call(date) === '[object Date]' && !isNaN(date.getTime())
+  );
+}
diff --git a/src/utils/validate/number.ts b/src/utils/validate/number.ts
index 47fbc44ad..254e580b2 100644
--- a/src/utils/validate/number.ts
+++ b/src/utils/validate/number.ts
@@ -1,3 +1,13 @@
+/* eslint-disable no-self-compare */
+
 export function isNumber(value: string): boolean {
   return /^\d+(\.\d+)?$/.test(value);
 }
+
+export function isNaN(value: any): boolean {
+  if (Number.isNaN) {
+    return Number.isNaN(value);
+  }
+
+  return value !== value;
+}