diff --git a/tools/train.py b/tools/train.py
index 84c1eec93aa..89c8548fc32 100644
--- a/tools/train.py
+++ b/tools/train.py
@@ -91,10 +91,6 @@ def merge_args(cfg, args):
 
     # enable automatic-mixed-precision training
     if args.amp is True:
-        optim_wrapper = cfg.optim_wrapper.get('type', 'OptimWrapper')
-        assert optim_wrapper in ['OptimWrapper', 'AmpOptimWrapper'], \
-            '`--amp` is not supported custom optimizer wrapper type ' \
-            f'`{optim_wrapper}.'
         cfg.optim_wrapper.type = 'AmpOptimWrapper'
         cfg.optim_wrapper.setdefault('loss_scale', 'dynamic')