diff --git a/paddlespeech/s2t/io/dataloader.py b/paddlespeech/s2t/io/dataloader.py
index 83183024..735d29da 100644
--- a/paddlespeech/s2t/io/dataloader.py
+++ b/paddlespeech/s2t/io/dataloader.py
@@ -389,6 +389,7 @@ class DataLoaderFactory():
                 config['mini_batch_size'] = args.ngpu
                 config['subsampling_factor'] = 1
                 config['num_encs'] = 1
+                config['shortest_first'] = False
             elif mode == 'valid':
                 config['manifest'] = config.dev_manifest
                 config['train_mode'] = False