To develop the passing ability and the ride comfort of crawler power chassis, a set of new suspension system was designed. Each suspension system has 5 separate damping units, and each one includes a hydraulic cylinder and a coil spring. The mathematic model was built according to the structure and mechanical properties of damping units. It was revealed fromKeq-H curve drawn from the mathematic model that the suspension system had nonlinear stiffness characteristic. 1∶4 crawler power chassis prototype and the performance tests were made. The chassis could achieve all terrain profiling and its maximum grade ability was about 60%, its maximum speed was about 3km/h. From the vibration acceleration curve, the absolute value of vibration acceleration was lower than 2.0m/s2. The crawler power chassis with new suspension system is good in its passing ability and ride comfort.