diff --git a/apps/wf/services.py b/apps/wf/services.py
index 7e802647..4efdada2 100755
--- a/apps/wf/services.py
+++ b/apps/wf/services.py
@@ -1,5 +1,6 @@
 import importlib
 from threading import Thread
+from django.core.cache import cache
 from apps.utils.sms import send_sms
 from apps.wf.serializers import TicketSimpleSerializer
 from apps.system.models import Dept, User
@@ -102,11 +103,25 @@ class WfService(object):
         生成工单流水号
         """
         if now is None:
-            now = datetime.now()
-        today = str(now)[:10]+' 00:00:00'
-        ticket_day_count_new = Ticket.objects.get_queryset(all=True).filter(
-            create_time__gte=today, create_time__lte=now, workflow=workflow).count()
-        return '%s_%04d%02d%02d%04d' % (workflow.sn_prefix, now.year, now.month, now.day, ticket_day_count_new)
+            now = timezone.now()
+        if timezone.is_aware(now):
+            now = timezone.localtime(now)
+        day_start = now.replace(hour=0, minute=0, second=0, microsecond=0)
+        day_end = day_start + timedelta(days=1)
+        sn_prefix = f"{workflow.sn_prefix}_{now:%Y%m%d}"
+        latest_sn = Ticket.objects.get_queryset(all=True).filter(
+            create_time__gte=day_start,
+            create_time__lt=day_end,
+            sn__startswith=sn_prefix,
+        ).order_by('-sn').values_list('sn', flat=True).first()
+
+        next_seq = 1
+        if latest_sn:
+            try:
+                next_seq = int(latest_sn[-4:]) + 1
+            except (TypeError, ValueError):
+                next_seq = 1
+        return f"{sn_prefix}{next_seq:04d}"
 
     @classmethod
     def get_next_state_by_transition_and_ticket_info(cls, ticket: Ticket,
@@ -328,17 +343,21 @@ class WfService(object):
                         save_ticket_data[key] = new_ticket_data[key]
             else:
                 save_ticket_data = new_ticket_data
-            ticket = Ticket.objects.create(workflow=workflow,
-                            state=start_state,
-                            create_by=handler,
-                            create_time=timezone.now(),
-                            act_state=Ticket.TICKET_ACT_STATE_DRAFT,
-                            belong_dept=handler.belong_dept,
-                            ticket_data=save_ticket_data, participant_type=1, participant=handler.id)  # 先创建出来
-           
-            sn = WfService.get_ticket_sn(ticket.workflow)  # 流水号
-            ticket.sn = sn
-            ticket.save()
+            ticket_now = timezone.now()
+            lock_now = timezone.localtime(ticket_now) if timezone.is_aware(ticket_now) else ticket_now
+            lock_key = f"ticket_sn:{workflow.sn_prefix}:{lock_now:%Y%m%d}"
+            with cache.lock(lock_key, timeout=10):
+                sn = WfService.get_ticket_sn(workflow, now=ticket_now)  # 流水号
+                ticket = Ticket.objects.create(workflow=workflow,
+                                state=start_state,
+                                create_by=handler,
+                                create_time=ticket_now,
+                                act_state=Ticket.TICKET_ACT_STATE_DRAFT,
+                                belong_dept=handler.belong_dept,
+                                ticket_data=save_ticket_data,
+                                participant_type=1,
+                                participant=handler.id,
+                                sn=sn)  # 先创建出来
             if not transition:
                 return ticket
             just_created = True  # 刚创建的工单不需要校验权限