A system for controlling a terminal application by means of a protective cover comprises: a terminal (12) and a protective cover (11) arranged on the terminal (12). The protective cover (11) comprises: at least one first position (111), at least one second position (112) and at least one track (113). Each first position (111) is located on the protective cover (11), and is configured to fix a magnet (13) when the magnet (13) is located at the first position (111). Each second position (112) is located on the protective cover (11), and is configured to fix the magnet (13) when the magnet (13) is located at the second position (112). The tracks (113) are respectively arranged between all the first positions (111) and all the second positions (112), and the tracks (113) are moving tracks of the magnet (13). The terminal (12) comprises: a detector (122), configured to detect the movement of the magnet (13); and a processor (121), configured to determine operation for a preset application according to the movement
