Disclosed is an MPEG portable sound reproducing system and a method for reproducing sound data compressed using the MPEG method. The inventive system includes power supply means for supplying operational power to the system, the power supply means being realized through a secondary battery; power processing means for rectifying power supplied from the power supply means to stable voltage and current; information display means for displaying numbers and combinations of letters related to operational states of the system; control means for controlling all operations of converting and reproducing sound data compressed using the MPEG method; data storage means for storing MPEG-compressed sound data in a designated address according to signals output from the control means; information selecting means for selecting general operations to reproduce, download, and apply selected sound data stored in the data storage means; sound reproducing means for converting sound data stored in the data storage means into a format audible to users according to signals output from the control means; and transmitting/receiving means for transmitting and receiving sound data and program data from external devices.