An exemplary heat dissipation apparatus includes a bracket, a reticular cover fixed to the bracket and a receiving space being defined with the bracket, and a tray received in the receiving space. The tray includes a first surface and a second surface. A number of first through holes is defined on the bracket. A number of second through holes is defined on the tray respectively corresponding to the first through holes, each of the second through holes extends obliquely from the first surface of the tray to the second surface of the tray relative to a vertical line of the first and second surfaces of the tray. A first magnet is installed on the first surface of the tray, a second magnet corresponding to the first magnet is installed on the bracket.