The invention discloses a hybrid magnetic circuit rotor of a permanent magnet synchronous motor. The hybrid magnetic circuit rotor comprises a rotor structure body, a built-in permanent magnet and surface-mounted permanent magnets. The rotor structure body is provided with a plurality of permanent magnet grooves. The built-in permanent magnet is embedded in the permanent magnet grooves. Each surface-mounted permanent magnet is provided with a permanent magnet groove directly facing to the surface-mounted permanent magnet. The surface-mounted permanent magnet is fixed on the outer circumference face of the rotor structure body. One surface-mounted permanent magnet and the built-in permanent magnet in the permanent magnet grooves which directly faces to the surface-mounted permanent magnet form one magnetic pole. The polarities of the neighboring magnetic poles are opposite. The rectangular axis inductance difference of the hybrid magnetic circuit rotor generates the reluctance torque, and the constant power operation range of the motor is widened. The surface-mounted permanent magnet provides the magnetic circuit capable of hinging a stator winding to the original leakage magnetic flux, the magnetic flux leakage coefficient is reduced, the power factor and the power density are improved, the width and the thickness of a magnetic separating bridge are increased, and the mechanical strength during the high speed running of the motor is improved.