diff --git a/src/datetime-picker/DatePicker.js b/src/datetime-picker/DatePicker.tsx
similarity index 87%
rename from src/datetime-picker/DatePicker.js
rename to src/datetime-picker/DatePicker.tsx
index c412dea47..4b07091bd 100644
--- a/src/datetime-picker/DatePicker.js
+++ b/src/datetime-picker/DatePicker.tsx
@@ -1,15 +1,23 @@
-import { ref, watch, computed, nextTick, onMounted } from 'vue';
+import { ref, watch, computed, nextTick, onMounted, PropType } from 'vue';
 
 // Utils
 import { isDate } from '../utils/validate/date';
-import { pick, padZero, createNamespace } from '../utils';
-import { times, sharedProps, getTrueValue, getMonthEndDay } from './utils';
+import { pick, range, padZero, createNamespace } from '../utils';
+import {
+  times,
+  ColumnType,
+  pickerKeys,
+  sharedProps,
+  getTrueValue,
+  getMonthEndDay,
+  DatetimePickerType,
+} from './utils';
 
 // Composition
 import { useExpose } from '../composables/use-expose';
 
 // Components
-import Picker, { pickerProps } from '../picker';
+import Picker from '../picker';
 
 const currentYear = new Date().getFullYear();
 const [createComponent] = createNamespace('date-picker');
@@ -17,17 +25,18 @@ const [createComponent] = createNamespace('date-picker');
 export default createComponent({
   props: {
     ...sharedProps,
+    modelValue: Date as PropType<Date>,
     type: {
-      type: String,
+      type: String as PropType<DatetimePickerType>,
       default: 'datetime',
     },
     minDate: {
-      type: Date,
+      type: Date as PropType<Date>,
       default: () => new Date(currentYear - 10, 0, 1),
       validator: isDate,
     },
     maxDate: {
-      type: Date,
+      type: Date as PropType<Date>,
       default: () => new Date(currentYear + 10, 11, 31),
       validator: isDate,
     },
@@ -36,22 +45,23 @@ export default createComponent({
   emits: ['confirm', 'cancel', 'change', 'update:modelValue'],
 
   setup(props, { emit, slots }) {
-    const formatValue = (value) => {
-      if (!isDate(value)) {
-        value = props.minDate;
+    const formatValue = (value?: Date) => {
+      if (isDate(value)) {
+        const timestamp = range(
+          value.getTime(),
+          props.minDate.getTime(),
+          props.maxDate.getTime()
+        );
+        return new Date(timestamp);
       }
-
-      value = Math.max(value, props.minDate.getTime());
-      value = Math.min(value, props.maxDate.getTime());
-
-      return new Date(value);
+      return props.minDate;
     };
 
     const picker = ref();
     const currentDate = ref(formatValue(props.modelValue));
 
-    const getBoundary = (type, value) => {
-      const boundary = props[`${type}Date`];
+    const getBoundary = (type: 'max' | 'min', value: Date) => {
+      const boundary = props[`${type}Date` as const];
       const year = boundary.getFullYear();
       let month = 1;
       let date = 1;
@@ -98,7 +108,7 @@ export default createComponent({
         currentDate.value
       );
 
-      let result = [
+      let result: Array<{ type: ColumnType; range: number[] }> = [
         {
           type: 'year',
           range: [minYear, maxYear],
@@ -205,7 +215,7 @@ export default createComponent({
       const { type } = props;
       const indexes = picker.value.getIndexes();
 
-      const getValue = (type) => {
+      const getValue = (type: ColumnType) => {
         let index = 0;
         originColumns.value.forEach((column, columnIndex) => {
           if (type === column.type) {
@@ -301,11 +311,10 @@ export default createComponent({
         v-slots={slots}
         ref={picker}
         columns={columns.value}
-        readonly={props.readonly}
         onChange={onChange}
         onCancel={onCancel}
         onConfirm={onConfirm}
-        {...pick(props, Object.keys(pickerProps))}
+        {...pick(props, pickerKeys)}
       />
     );
   },
diff --git a/src/datetime-picker/README.md b/src/datetime-picker/README.md
index 7a3f7e738..0c5f0b65a 100644
--- a/src/datetime-picker/README.md
+++ b/src/datetime-picker/README.md
@@ -284,8 +284,8 @@ export default {
 | show-toolbar | Whether to show toolbar | _boolean_ | `true` |
 | loading | Whether to show loading prompt | _boolean_ | `false` |
 | readonly | Whether to be readonly | _boolean_ | `false` |
-| filter | Option filter | _(type, vals) => vals_ | - |
-| formatter | Option text formatter | _(type, val) => val_ | - |
+| filter | Option filter | _(type: string, values: string[]) => string[]_ | - |
+| formatter | Option text formatter | _(type: string, value: string) => string_ | - |
 | columns-order | Array for ordering columns, where item can be set to<br> `year`, `month`, `day`, `hour` and `minute` | _string[]_ | - |
 | item-height | Option height, supports `px` `vw` `vh` `rem` unit, default `px` | _number \| string_ | `44` |
 | visible-item-count | Count of visible columns | _number \| string_ | `6` |
diff --git a/src/datetime-picker/README.zh-CN.md b/src/datetime-picker/README.zh-CN.md
index 345e7e046..27ebfbe0d 100644
--- a/src/datetime-picker/README.zh-CN.md
+++ b/src/datetime-picker/README.zh-CN.md
@@ -293,8 +293,8 @@ export default {
 | show-toolbar | 是否显示顶部栏 | _boolean_ | `true` |
 | loading | 是否显示加载状态 | _boolean_ | `false` |
 | readonly | 是否为只读状态，只读状态下无法切换选项 | _boolean_ | `false` |
-| filter | 选项过滤函数 | _(type, vals) => vals_ | - |
-| formatter | 选项格式化函数 | _(type, val) => val_ | - |
+| filter | 选项过滤函数 | _(type: string, values: string[]) => string[]_ | - |
+| formatter | 选项格式化函数 | _(type: string, value: string) => string_ | - |
 | columns-order | 自定义列排序数组, 子项可选值为<br> `year`、`month`、`day`、`hour`、`minute` | _string[]_ | - |
 | item-height | 选项高度，支持 `px` `vw` `vh` `rem` 单位，默认 `px` | _number \| string_ | `44` |
 | visible-item-count | 可见的选项个数 | _number \| string_ | `6` |
diff --git a/src/datetime-picker/TimePicker.js b/src/datetime-picker/TimePicker.tsx
similarity index 86%
rename from src/datetime-picker/TimePicker.js
rename to src/datetime-picker/TimePicker.tsx
index 5e8fc9ac2..880b8e9a2 100644
--- a/src/datetime-picker/TimePicker.js
+++ b/src/datetime-picker/TimePicker.tsx
@@ -1,20 +1,27 @@
 import { ref, watch, computed, nextTick, onMounted } from 'vue';
 
 // Utils
-import { pick, range, padZero, createNamespace } from '../utils';
-import { times, sharedProps } from './utils';
+import {
+  pick,
+  range,
+  padZero,
+  createNamespace,
+  ComponentInstance,
+} from '../utils';
+import { times, sharedProps, pickerKeys } from './utils';
 
 // Composition
 import { useExpose } from '../composables/use-expose';
 
 // Components
-import Picker, { pickerProps } from '../picker';
+import Picker from '../picker';
 
 const [createComponent] = createNamespace('time-picker');
 
 export default createComponent({
   props: {
     ...sharedProps,
+    modelValue: String,
     minHour: {
       type: [Number, String],
       default: 0,
@@ -36,7 +43,7 @@ export default createComponent({
   emits: ['confirm', 'cancel', 'change', 'update:modelValue'],
 
   setup(props, { emit, slots }) {
-    const formatValue = (value) => {
+    const formatValue = (value?: string) => {
       const { minHour, maxHour, maxMinute, minMinute } = props;
 
       if (!value) {
@@ -44,13 +51,13 @@ export default createComponent({
       }
 
       let [hour, minute] = value.split(':');
-      hour = padZero(range(hour, minHour, maxHour));
-      minute = padZero(range(minute, minMinute, maxMinute));
+      hour = padZero(range(+hour, +minHour, +maxHour));
+      minute = padZero(range(+minute, +minMinute, +maxMinute));
 
       return `${hour}:${minute}`;
     };
 
-    const picker = ref();
+    const picker = ref<ComponentInstance>();
     const currentDate = ref(formatValue(props.modelValue));
 
     const ranges = computed(() => [
@@ -97,12 +104,12 @@ export default createComponent({
       ];
 
       nextTick(() => {
-        picker.value.setValues(values);
+        picker.value!.setValues(values);
       });
     };
 
     const updateInnerValue = () => {
-      const [hourIndex, minuteIndex] = picker.value.getIndexes();
+      const [hourIndex, minuteIndex] = picker.value!.getIndexes();
       const [hourColumn, minuteColumn] = originColumns.value;
 
       const hour = hourColumn.values[hourIndex] || hourColumn.values[0];
@@ -173,11 +180,10 @@ export default createComponent({
         v-slots={slots}
         ref={picker}
         columns={columns.value}
-        readonly={props.readonly}
         onChange={onChange}
         onCancel={onCancel}
         onConfirm={onConfirm}
-        {...pick(props, Object.keys(pickerProps))}
+        {...pick(props, pickerKeys)}
       />
     );
   },
diff --git a/src/datetime-picker/index.js b/src/datetime-picker/index.tsx
similarity index 87%
rename from src/datetime-picker/index.js
rename to src/datetime-picker/index.tsx
index fac3a4136..9164633d0 100644
--- a/src/datetime-picker/index.js
+++ b/src/datetime-picker/index.tsx
@@ -1,5 +1,5 @@
 import { ref } from 'vue';
-import { pick, createNamespace } from '../utils';
+import { pick, createNamespace, ComponentInstance } from '../utils';
 import { useExpose } from '../composables/use-expose';
 import TimePicker from './TimePicker';
 import DatePicker from './DatePicker';
@@ -13,10 +13,11 @@ export default createComponent({
   props: {
     ...TimePicker.props,
     ...DatePicker.props,
+    modelValue: [String, Date],
   },
 
   setup(props, { attrs, slots }) {
-    const root = ref();
+    const root = ref<ComponentInstance>();
 
     useExpose({
       getPicker: () => root.value?.getPicker(),
diff --git a/src/datetime-picker/utils.ts b/src/datetime-picker/utils.ts
index 623d296a3..3500d7b88 100644
--- a/src/datetime-picker/utils.ts
+++ b/src/datetime-picker/utils.ts
@@ -1,20 +1,34 @@
+import { PropType } from 'vue';
 import { isNaN } from '../utils/validate/number';
 import { pickerProps } from '../picker';
 
+export type ColumnType = 'year' | 'month' | 'day' | 'hour' | 'minute';
+
+export type DatetimePickerType =
+  | 'date'
+  | 'time'
+  | 'datetime'
+  | 'datehour'
+  | 'month-day'
+  | 'year-month';
+
 export const sharedProps = {
   ...pickerProps,
-  filter: Function,
-  modelValue: null,
-  columnsOrder: Array,
+  filter: Function as PropType<(type: string, values: string[]) => string[]>,
+  columnsOrder: Array as PropType<ColumnType[]>,
   formatter: {
-    type: Function,
-    default: (type: string, value: unknown) => value,
+    type: Function as PropType<(type: string, value: string) => string>,
+    default: (type: string, value: string) => value,
   },
 };
 
-export function times(n: number, iteratee: (index: number) => any[]) {
+export const pickerKeys = Object.keys(pickerProps) as Array<
+  keyof typeof pickerProps
+>;
+
+export function times<T>(n: number, iteratee: (index: number) => T) {
   let index = -1;
-  const result = Array(n);
+  const result: T[] = Array(n);
 
   while (++index < n) {
     result[index] = iteratee(index);
diff --git a/src/utils/validate/date.ts b/src/utils/validate/date.ts
index d06fd6696..d62b3c9c3 100644
--- a/src/utils/validate/date.ts
+++ b/src/utils/validate/date.ts
@@ -1,8 +1,8 @@
 import { isNaN } from './number';
 
-export function isDate(val: Date): val is Date {
+export function isDate(val: unknown): val is Date {
   return (
     Object.prototype.toString.call(val) === '[object Date]' &&
-    !isNaN(val.getTime())
+    !isNaN((val as Date).getTime())
   );
 }