The invention relates to a motor driving system for a vehicle bidirectional quasi-Z-source inverter. The motor driving system comprises a speed regulation control module, a sensor unit, and a power supply module, a bidirectional quasi-Z-source preceding-stage passive network, a three-phase bridge type inverter and a motor which are connected in sequence, wherein the bidirectional quasi-Z-source preceding-stage passive network and the three-phase bridge type inverter form the bidirectional quasi-Z-source inverter; the speed regulation control module is connected with the sensor unit and the bidirectional quasi-Z-source inverter separately; and the bidirectional quasi-Z-source preceding-stage passive network comprises inductors L1 and L2, capacitors C1 and C2, an IGBT switch tube S7 and a diode D7. Compared with the prior art, the bidirectional quasi-Z-source inverter system established by the invention, taken as the single-stage inverter system, can replace the two-stage conversion DC/DC and DC/AC conversion in the conventional electric driving field to avoid voltage fluctuation of the battery pack and maintain the stable and adjustable direct bus voltage; and in addition, the problem of dead time existing in the conventional inverter is prevented, so that the output voltage distortion can be lowered, and the torque pulsation and electromagnetic noises can be reduced.