In the design of the music player system, the smooth audio data can improve the quality of audio playback. This design uses STC12C5A60S2 as the main controller, VS1003 as a music signal decoding chip, CH378 as the interface chip for reading USB and SD card. The chip CH378 can be connected directly to the U disk/SD card, it optimizes the process that SCM obtains information, simplifies the procedures, at the same time has the advantage of larger data cache RAM , and supports FAT file manipulation, so music played more smoothly, achieving external mass storage and portable embedded systems, it is useful for increasing demand of storage space in the market.