diff --git a/uncloud_pay/models.py b/uncloud_pay/models.py
index 82005c9..1d16eab 100644
--- a/uncloud_pay/models.py
+++ b/uncloud_pay/models.py
@@ -553,8 +553,14 @@ class Bill(models.Model):
 
     @property
     def final(self):
-        # A bill is final when its ending date is passed.
-        return self.ending_date < timezone.now()
+        # A bill is final when its ending date is passed, or when all of its
+        # orders have been terminated.
+        every_order_terminated = True
+        billing_period_is_over = self.ending_date < timezone.now()
+        for order in self.order_set.all():
+            every_order_terminated = every_order_terminated and order.is_terminated
+
+        return billing_period_is_over or every_order_terminated
 
     def activate_products(self):
         for order in self.order_set.all():
@@ -850,6 +856,14 @@ class Order(models.Model):
                                     on_delete=models.PROTECT,
                                     blank=True,
                                     null=True)
+    @property
+    def is_terminated(self):
+        return self.ending_date != None and self.ending_date < timezone.now()
+
+    def terminate(self):
+        if not self.is_terminated:
+            self.ending_date = timezone.now()
+            self.save()
 
     # Trigger initial bill generation at order creation.
     def save(self, *args, **kwargs):
diff --git a/uncloud_pay/views.py b/uncloud_pay/views.py
index 55f1940..18b76e4 100644
--- a/uncloud_pay/views.py
+++ b/uncloud_pay/views.py
@@ -313,3 +313,15 @@ class AdminOrderViewSet(mixins.ListModelMixin,
 
     def get_queryset(self):
         return Order.objects.all()
+
+    @action(detail=True, methods=['post'])
+    def terminate(self, request, pk):
+        order = self.get_object()
+        if order.is_terminated:
+            return Response(
+                    {'error': 'Order is already terminated.'},
+                    status=status.HTTP_500_INTERNAL_SERVER_ERROR)
+
+        else:
+            order.terminate()
+            return Response({}, status=status.HTTP_200_OK)