Chinese contrasts aspirated and unaspirated sounds while Japanese contrasts voiceless and voiced sounds. Consequently, it is considered to be hard for Chinese speakers to distinguish voiceless from voiced. I trained students on distinguishing voiceless and voiced sounds. The training included distinguishing single and geminate sounds because geminate sounds might be difficult for them. I checked whether or not their listening ability would be improved by giving the same test before and after the training. As the results, their listening ability was improved 10%. The participants of this training began learning Japanese as the second foreign language a month before the training.