The hydraulic antikink system is an important component equipped in lowfloor trams to improve the riding quality, stability and curving behavior of the vehicles. The system has two functions in antikink and lateral damping. A mathematical model for damping properties was established based on the operating mechanisms of the system. Furthermore, the influence of throttle valve and pressure limiting valve on the damping characteristics of the system was investigated by simulation. The calculating curve of the damping characteristics coincides with the experimental curve, which proves the correctness of the damping mathematical model.