worked out the issue

dolphinscheduler-ui/src/views/projects/workflow/definition/components/start-modal.tsx

@@ -44,7 +44,8 @@ import {
   NSwitch,
   NCheckbox,
   NDatePicker,
-  NRadioButton
+  NRadioButton,
+  NInputNumber
 } from 'naive-ui'
 import {
   ArrowDownOutlined,
@@ -75,7 +76,6 @@ export default defineComponent({
   props,
   emits: ['update:show', 'update:row', 'updateList'],
   setup(props, ctx) {
-    const parallelismRef = ref(false)
     const { t } = useI18n()
     const route = useRoute()
     const { startState } = useForm()
@@ -296,7 +296,6 @@ export default defineComponent({
     return {
       t,
       showTaskDependType,
-      parallelismRef,
       hideModal,
       handleStart,
       generalWarningTypeListOptions,
@@ -505,16 +504,13 @@ export default defineComponent({
                     label={t('project.workflow.parallelism')}
                     path='expectedParallelismNumber'
                   >
-                    <NCheckbox v-model:checked={this.parallelismRef}>
-                      {t('project.workflow.custom_parallelism')}
-                    </NCheckbox>
-                    <NInput
-                      allowInput={this.trim}
-                      disabled={!this.parallelismRef}
+                    <NInputNumber
                       placeholder={t(
                         'project.workflow.please_enter_parallelism'
                       )}
                       v-model:value={this.startForm.expectedParallelismNumber}
+                      max='100'
+                      min='1'
                     />
                   </NFormItem>
                 )}

dolphinscheduler-ui/src/views/projects/workflow/definition/components/use-form.ts

@@ -66,7 +66,7 @@ export const useForm = () => {
       tenantCode: 'default',
       environmentCode: null,
       startParams: null,
-      expectedParallelismNumber: '',
+      expectedParallelismNumber: '2',
       dryRun: 0,
       testFlag: 0,
       version: null,