A proprietary portable audio player system for protecting digital content copyrights, which includes a proprietary portable audio player, a web access interface, and an online music server. The proprietary portable audio player has a hardware unique device identity. The proprietary portable audio player has a playback token acquirement mode and uses a first transmission medium to link with the online music server to thereby obtain a playback token for a corresponding music file playback. The online music server pre-stores a plurality of music files with compression formats, a plurality of playback tokens, and a mapping table. When a playback token signal from the web access interface is received, the online music server accordingly issues a playback token corresponding to a specific music file, updates the mapping table, and sends the playback token to the proprietary portable audio player through the first transmission medium.