An exercise assistant system and method for managing an exercise pattern in conjunction with music is provided. The exercise assistant system builds a reference exercise schedule on the basis of user information; designates at least one music file for the reference exercise schedule; stores the reference exercise schedule and the music file; outputs guidance information and the music file in sound on the basis of the reference exercise schedule; displays a reference exercise pattern and an actual exercise pattern in a form of graph; and resets the reference exercise schedule and the music file on the basis of a biological change of the user during exercise. The exercise assistant system and method enables adjustment of the exercise amount and level according to the user's exercise achievement and physical variation during the exercise, such that it is possible to effectively assist the user's exercise. Also, in the exercise assistant system, the music files are selected automatically on the basis of the predetermined designated conditions making possible user enjoyment of the music in various sequences.