The invention discloses a compound automobile suspension system, which is installed between an automobile frame and an axle, and comprises two leaf springs symmetrically located below a vehicle body.The two ends of the leaf springs are hinged to the frame. The extension direction of the leaf springs is consistent with the extension direction of the frame. The middles of the leaf springs are fixedly connected with the axle. An air spring and a shock absorber are installed between the middles of the leaf springs and the frame. The air spring is connected with an air spring height adjustment mechanism. The air spring and the leaf springs together work as elastic elements to bear loads, the leaf springs also play a guiding role, the shock absorber and the air spring are connected with the leaf springs, so that the structure is simple and compact, and implementation is easy. By controlling the air inlet and air outlet of the air spring, the working height of the vehicle body can be kept constant under different loads, the natural frequency of the suspension system can also be kept basically unchanged under different loads, and the smoothness of the suspension system is improved throughthe excellent ability of absorbing high-frequency vibration.