Active heat dissipation structure attached to passive heat dissipation piece

The invention discloses an active heat dissipation structure attached to a passive heat dissipation piece. The heat dissipation structure comprises a fan, an outer frame on which the fan is arranged, and two mounting pieces; the outer frame comprises two first assembling parts which are arranged on two opposite sides of the outer frame; the two mounting pieces are arranged on the passive heat dissipation piece and connected with the outer frame in an assembled mode, and each mounting piece is provided with a first mounting part connected with one of the two first assembling parts in an assembled mode. Furthermore, each first assembling part comprises a track provided with a plurality of positioning points and a guide groove parallel to the track. Each first mounting part comprises at least one elastic sheet which is stressed to move in the track and can be limited by one of the positioning points, and the guide block that can slide in the guide groove when being stressed. And the outer frame can change the po