In order to get the knowledge of Effects of four bar linkage clearance on dynamic characteristic of active suspension for tracked vehicle, on the basis of electro-hydraulic active suspension designed for a certain tracked vehicle with high speed, the virtual test co-simulation model of vehicle with active suspension was built through the software of Motion and AMEsim, clearance joint of linkage was modeled by the tools of contact element, and the influence of various situations of joint clearance to the dynamic characteristic were analyzed, the results indicate that clearance will cause the shock force output from the actuator together with the pulse fluctuation of the wheel acceleration signals, and the actuator will need larger swing displacement to control the suspension force, for which the clearance will bring the nonlinear increase of power consummation.