The invention discloses an air suspension system of a car. According to the air suspension system of the car, rubber air springs are banded tightly on an upper cap through upper shroud rings, and banded tightly on a lower base through lower shroud rings, and thus a rubber air spring assembly is formed and mounted on a vibration damper; the upper end of an air inlet lever is fixed to a fixing plate, the lower part of the air inlet lever can slide in a lower base hole, and a sealing ring is mounted in the hole of the lower base; an air inlet nipple is mounted at the lower end of the lower base hole where the air inlet lever can slide; the upper end of an air outlet lever is fixed to the fixing plate, the lower part of the air outlet lever can slide in a lower base hole, and a sealing ring is mounted in the lower base hole; an upper connector is fixed to the upper cap, a lower connector is fixed to the vibration damper, the upper connector is connected with a car body, and the lower connector is connected with a car axle. The air suspension system is suitable for cars, and can support weight of the car body, absorb the impact transmitted to the car body by a rough road, self-adjust and stabilize to the original designed height according to changes of loads, and can absorb the energy generated in the process of vibration to reduce the vibration.