diff --git a/account/tasks.py b/account/tasks.py
index 12c1587d..51359991 100644
--- a/account/tasks.py
+++ b/account/tasks.py
@@ -1,14 +1,13 @@
 import logging
-
-from celery import shared_task
+import dramatiq
 
 from options.options import SysOptions
-from utils.shortcuts import send_email
+from utils.shortcuts import send_email, DRAMATIQ_WORKER_ARGS
 
 logger = logging.getLogger(__name__)
 
 
-@shared_task
+@dramatiq.actor(**DRAMATIQ_WORKER_ARGS(max_retries=3))
 def send_email_async(from_name, to_email, to_name, subject, content):
     if not SysOptions.smtp_config:
         return
diff --git a/account/views/oj.py b/account/views/oj.py
index 095f1e40..2d26e484 100644
--- a/account/views/oj.py
+++ b/account/views/oj.py
@@ -302,11 +302,11 @@ class ApplyResetPasswordAPI(APIView):
             "link": f"{SysOptions.website_base_url}/reset-password/{user.reset_password_token}"
         }
         email_html = render_to_string("reset_password_email.html", render_data)
-        send_email_async.delay(from_name=SysOptions.website_name_shortcut,
-                               to_email=user.email,
-                               to_name=user.username,
-                               subject=f"Reset your password",
-                               content=email_html)
+        send_email_async.send(from_name=SysOptions.website_name_shortcut,
+                              to_email=user.email,
+                              to_name=user.username,
+                              subject=f"Reset your password",
+                              content=email_html)
         return self.success("Succeeded")
 
 
diff --git a/contest/views/admin.py b/contest/views/admin.py
index 9adb45ad..66addb15 100644
--- a/contest/views/admin.py
+++ b/contest/views/admin.py
@@ -234,7 +234,7 @@ class DownloadContestSubmissions(APIView):
 
         exclude_admin = request.GET.get("exclude_admin") == "1"
         zip_path = self._dump_submissions(contest, exclude_admin)
-        delete_files.apply_async((zip_path,), countdown=300)
+        delete_files.send_with_options(args=(zip_path,), delay=300_000)
         resp = FileResponse(open(zip_path, "rb"))
         resp["Content-Type"] = "application/zip"
         resp["Content-Disposition"] = f"attachment;filename={os.path.basename(zip_path)}"
diff --git a/deploy/requirements.txt b/deploy/requirements.txt
index 4feaa4d5..8d12c69d 100644
--- a/deploy/requirements.txt
+++ b/deploy/requirements.txt
@@ -1,6 +1,3 @@
-amqp==2.4.2
-billiard==3.5.0.5
-celery==4.2.1
 certifi==2019.3.9
 chardet==3.0.4
 coverage==4.5.3
@@ -15,7 +12,6 @@ flake8-quotes==1.0.0
 gunicorn==19.9.0
 idna==2.8
 jsonfield==2.0.2
-kombu==4.4.0
 mccabe==0.6.1
 otpauth==1.0.1
 Pillow==5.4.1
@@ -30,5 +26,6 @@ redis==3.2.0
 requests==2.21.0
 six==1.12.0
 urllib3==1.24.1
-vine==1.2.0
 XlsxWriter==1.1.5
+django-dramatiq==0.5.0
+dramatiq==1.3.0
\ No newline at end of file
diff --git a/deploy/supervisord.conf b/deploy/supervisord.conf
index 0eca7211..b1740466 100644
--- a/deploy/supervisord.conf
+++ b/deploy/supervisord.conf
@@ -38,12 +38,12 @@ startsecs=5
 stopwaitsecs = 5
 killasgroup=true
 
-[program:celery]
-command=celery -A oj worker -l warning --autoscale 2,%(ENV_MAX_WORKER_NUM)s
+[program:dramatiq]
+command=python3 manage.py rundramatiq --no-reload --processes %(ENV_MAX_WORKER_NUM)s --threads 4
 directory=/app/
 user=nobody
-stdout_logfile=/data/log/celery.log
-stderr_logfile=/data/log/celery.log
+stdout_logfile=/data/log/dramatiq.log
+stderr_logfile=/data/log/dramatiq.log
 autostart=true
 autorestart=true
 startsecs=5
diff --git a/judge/dispatcher.py b/judge/dispatcher.py
index 6f3a9434..5466df85 100644
--- a/judge/dispatcher.py
+++ b/judge/dispatcher.py
@@ -26,7 +26,7 @@ def process_pending_task():
         # 防止循环引入
         from judge.tasks import judge_task
         data = json.loads(cache.rpop(CacheKey.waiting_queue).decode("utf-8"))
-        judge_task.delay(**data)
+        judge_task.send(**data)
 
 
 class DispatcherBase(object):
diff --git a/judge/tasks.py b/judge/tasks.py
index a5c18182..8a1794a1 100644
--- a/judge/tasks.py
+++ b/judge/tasks.py
@@ -1,12 +1,12 @@
-from __future__ import absolute_import, unicode_literals
-from celery import shared_task
+import dramatiq
 
 from account.models import User
 from submission.models import Submission
 from judge.dispatcher import JudgeDispatcher
+from utils.shortcuts import DRAMATIQ_WORKER_ARGS
 
 
-@shared_task
+@dramatiq.actor(**DRAMATIQ_WORKER_ARGS())
 def judge_task(submission_id, problem_id):
     uid = Submission.objects.get(id=submission_id).user_id
     if User.objects.get(id=uid).is_disabled:
diff --git a/oj/__init__.py b/oj/__init__.py
index 23fc183a..e69de29b 100644
--- a/oj/__init__.py
+++ b/oj/__init__.py
@@ -1,6 +0,0 @@
-from __future__ import absolute_import, unicode_literals
-
-# Django starts so that shared_task will use this app.
-from .celery import app as celery_app
-
-__all__ = ["celery_app"]
diff --git a/oj/celery.py b/oj/celery.py
deleted file mode 100644
index 4f24c7e7..00000000
--- a/oj/celery.py
+++ /dev/null
@@ -1,18 +0,0 @@
-from __future__ import absolute_import, unicode_literals
-import os
-from celery import Celery
-from django.conf import settings
-
-# set the default Django settings module for the "celery" program.
-os.environ.setdefault("DJANGO_SETTINGS_MODULE", "oj.settings")
-
-
-app = Celery("oj")
-
-# Using a string here means the worker will not have to
-# pickle the object when using Windows.
-app.config_from_object("django.conf:settings")
-
-# load task modules from all registered Django app configs.
-app.autodiscover_tasks(lambda: settings.INSTALLED_APPS)
-# app.autodiscover_tasks()
diff --git a/oj/settings.py b/oj/settings.py
index 2cfa9c8d..37a85855 100644
--- a/oj/settings.py
+++ b/oj/settings.py
@@ -33,7 +33,8 @@ VENDOR_APPS = (
     'django.contrib.messages',
     'django.contrib.staticfiles',
     'rest_framework',
-    'raven.contrib.django.raven_compat'
+    'raven.contrib.django.raven_compat',
+    'django_dramatiq',
 )
 LOCAL_APPS = (
     'account',
@@ -164,6 +165,11 @@ LOGGING = {
            'level': 'ERROR',
            'propagate': True,
        },
+        'dramatiq': {
+            'handlers': LOGGING_HANDLERS,
+            'level': 'DEBUG',
+            'propagate': False,
+        },
        '': {
            'handlers': LOGGING_HANDLERS,
            'level': 'WARNING',
@@ -202,11 +208,32 @@ CACHES = {
 SESSION_ENGINE = "django.contrib.sessions.backends.cache"
 SESSION_CACHE_ALIAS = "default"
 
-CELERY_RESULT_BACKEND = f"{REDIS_URL}/2"
-BROKER_URL = f"{REDIS_URL}/3"
-CELERY_TASK_SOFT_TIME_LIMIT = CELERY_TASK_TIME_LIMIT = 180
-CELERY_ACCEPT_CONTENT = ["json"]
-CELERY_TASK_SERIALIZER = "json"
+DRAMATIQ_BROKER = {
+    "BROKER": "dramatiq.brokers.redis.RedisBroker",
+    "OPTIONS": {
+        "url": f"{REDIS_URL}/4",
+    },
+    "MIDDLEWARE": [
+        # "dramatiq.middleware.Prometheus",
+        "dramatiq.middleware.AgeLimit",
+        "dramatiq.middleware.TimeLimit",
+        "dramatiq.middleware.Callbacks",
+        "dramatiq.middleware.Retries",
+        # "django_dramatiq.middleware.AdminMiddleware",
+        "django_dramatiq.middleware.DbConnectionsMiddleware"
+    ]
+}
+
+DRAMATIQ_RESULT_BACKEND = {
+    "BACKEND": "dramatiq.results.backends.redis.RedisBackend",
+    "BACKEND_OPTIONS": {
+        "url": f"{REDIS_URL}/4",
+    },
+    "MIDDLEWARE_OPTIONS": {
+        "result_ttl": None
+    }
+}
+
 RAVEN_CONFIG = {
     'dsn': 'https://b200023b8aed4d708fb593c5e0a6ad3d:1fddaba168f84fcf97e0d549faaeaff0@sentry.io/263057'
 }
diff --git a/problem/views/admin.py b/problem/views/admin.py
index e06ff619..5a5268aa 100644
--- a/problem/views/admin.py
+++ b/problem/views/admin.py
@@ -300,8 +300,6 @@ class ProblemAPI(ProblemBase):
         except Problem.DoesNotExist:
             return self.error("Problem does not exists")
         ensure_created_by(problem, request.user)
-        if Submission.objects.filter(problem=problem).exists():
-            return self.error("Can't delete the problem as it has submissions")
         d = os.path.join(settings.TEST_CASE_DIR, problem.test_case_id)
         if os.path.isdir(d):
             shutil.rmtree(d, ignore_errors=True)
@@ -541,7 +539,7 @@ class ExportProblemAPI(APIView):
         with zipfile.ZipFile(path, "w") as zip_file:
             for index, problem in enumerate(problems):
                 self.process_one_problem(zip_file=zip_file, user=request.user, problem=problem, index=index + 1)
-        delete_files.apply_async((path,), countdown=300)
+        delete_files.send_with_options(args=(path,), delay=300_000)
         resp = FileResponse(open(path, "rb"))
         resp["Content-Type"] = "application/zip"
         resp["Content-Disposition"] = f"attachment;filename=problem-export.zip"
diff --git a/submission/views/admin.py b/submission/views/admin.py
index d2312c04..87972561 100644
--- a/submission/views/admin.py
+++ b/submission/views/admin.py
@@ -18,5 +18,5 @@ class SubmissionRejudgeAPI(APIView):
         submission.statistic_info = {}
         submission.save()
 
-        judge_task.delay(submission.id, submission.problem.id)
+        judge_task.send(submission.id, submission.problem.id)
         return self.success()
diff --git a/submission/views/oj.py b/submission/views/oj.py
index 8501efb4..0f7c4a58 100644
--- a/submission/views/oj.py
+++ b/submission/views/oj.py
@@ -80,7 +80,7 @@ class SubmissionAPI(APIView):
                                                contest_id=data.get("contest_id"))
         # use this for debug
         # JudgeDispatcher(submission.id, problem.id).judge()
-        judge_task.delay(submission.id, problem.id)
+        judge_task.send(submission.id, problem.id)
         if hide_id:
             return self.success()
         else:
diff --git a/utils/api/api.py b/utils/api/api.py
index 3f3f24ca..a603bfb9 100644
--- a/utils/api/api.py
+++ b/utils/api/api.py
@@ -1,7 +1,6 @@
 import functools
 import json
 import logging
-from collections import OrderedDict
 
 from django.http import HttpResponse, QueryDict
 from django.utils.decorators import method_decorator
@@ -98,6 +97,8 @@ class APIView(View):
         elif isinstance(errors, list):
             return self.extract_errors(errors[0], key)
 
+        return key, errors
+
     def invalid_serializer(self, serializer):
         key, error = self.extract_errors(serializer.errors)
         if key == "non_field_errors":
diff --git a/utils/shortcuts.py b/utils/shortcuts.py
index ea0d094f..1569ce31 100644
--- a/utils/shortcuts.py
+++ b/utils/shortcuts.py
@@ -81,3 +81,7 @@ def send_email(smtp_config, from_name, to_email, to_name, subject, content):
 
 def get_env(name, default=""):
     return os.environ.get(name, default)
+
+
+def DRAMATIQ_WORKER_ARGS(time_limit=3600_000, max_retries=0, max_age=7200_000):
+    return {"max_retries": max_retries, "time_limit": time_limit, "max_age": max_age}
diff --git a/utils/tasks.py b/utils/tasks.py
index 442b0bc4..26a21805 100644
--- a/utils/tasks.py
+++ b/utils/tasks.py
@@ -1,8 +1,10 @@
 import os
-from celery import shared_task
+import dramatiq
+
+from utils.shortcuts import DRAMATIQ_WORKER_ARGS
 
 
-@shared_task
+@dramatiq.actor(**DRAMATIQ_WORKER_ARGS())
 def delete_files(*args):
     for item in args:
         try: