diff --git a/apps/pm/models.py b/apps/pm/models.py
index 82f1d699..975597b4 100644
--- a/apps/pm/models.py
+++ b/apps/pm/models.py
@@ -1,6 +1,8 @@
 from django.db import models
 from apps.utils.models import CommonADModel, CommonBDModel, BaseModel
 from apps.mtm.models import Material, Mgroup, RoutePack, Route
+from datetime import datetime
+from django.db.models import Max
 
 # Create your models here.
 
@@ -52,6 +54,18 @@ class Utask(CommonBDModel):
     start_date = models.DateField('计划开工日期')
     end_date = models.DateField('计划完工日期')
 
+    @classmethod
+    def get_a_number(cls):
+        today_str = datetime.now().strftime('%Y%m%d')
+        prefix = "RW"
+        last_record = Utask.objects.filter(number__startswith=f"{prefix}-{today_str}") \
+                                       .aggregate(Max('number'))['number__max']
+        if last_record:
+            last_number = int(last_record.split('-')[-1]) + 1
+        else:
+            last_number = 1
+        return f"{prefix}-{today_str}-{last_number:02d}"
+
 
 class Mtask(CommonADModel):
     """
diff --git a/apps/pm/serializers.py b/apps/pm/serializers.py
index 5bea0059..0eb28dfa 100644
--- a/apps/pm/serializers.py
+++ b/apps/pm/serializers.py
@@ -24,7 +24,12 @@ class UtaskSerializer(CustomModelSerializer):
     class Meta:
         model = Utask
         fields = '__all__'
+        read_only_fields = ["number"]
 
+    def create(self, validated_data):
+        validated_data["number"] = Utask.get_a_number()
+        return super().create(validated_data)
+    
     def validate(self, attrs):
         end_date = attrs['end_date']
         start_date = attrs['start_date']
@@ -42,8 +47,7 @@ class UtaskSerializer(CustomModelSerializer):
     def update(self, instance, validated_data):
         if instance.state != Utask.UTASK_CREATED:
             raise ValidationError('任务非创建中不可编辑')
-        new_data = {key: validated_data[key] for key in [
-            'number', 'count', 'start_date', 'end_date']}
+        new_data = {key: validated_data[key] for key in ['count', 'start_date', 'end_date']}
         return super().update(instance, new_data)