A motor controller, including: a control box including an inner wall; a circuit board; a dissipater; an IGBT module; and an insulating piece. The circuit board is disposed inside the controller box. The dissipater is disposed on the inner wall of the control box. The IGBT module is disposed on the dissipater and is in electric connection with the circuit board. The insulating piece is disposed between the dissipater and the controller and prevents the dissipater from contacting with the control box.