The invention discloses an electromobile range extender and a control method. The electromobile range extender consists of an engine, an engine ECU (Electronic Control Unit), an electronic throttle valve controller, a direct current starter, an engine speed sensor, an alternating current permanent magnet synchronous motor, a three-phase full-control rectifier, filter capacitors, voltage sampling resistors, a current sensor, a freewheeling diode and a three-phase full-control rectifying voltage regulation phase-shift trigger, wherein the engine is started by the starter and then drags the alternating current permanent magnet synchronous motor to generate electricity and output the three-phase alternating current voltage to the thyristor three-phase full-control rectifier; after the direct current pulsating voltage output by the rectifier is filtered by the two filter capacitors connected in series, the three-phase full-control rectifying voltage regulation phase-shift trigger acquires the output voltage and current of the range extender to obtain the output power, and adjusts a conduction angle according to the power to realize closed-loop control of the power; and the electronic throttle valve controller acquires the engine speed, adjusts the throttle valve opening, and realizes the closed-loop control of the engine speed. The electromobile range extender and the control method have the advantages of low cost and high control precision.