A coordination device was constructed to solve the problem that the front and rear hydro pneumatic suspension of off-highway dump trucks cannot be directly connected, which was caused by the great changes of the front and rear axle load ratio in no-load and full load conditions. A simulation analysis was carried out under a half car model, in which the front and rear hydro pneumatic suspensions were connected by the coordination device. The simulation was divided into the front and rear wheels order thought the step and sine sweep excitation conditions. Sprung mass vertical acceleration, pitch angel acceleration and output force characteristics of suspensions were selected as the stand to evaluate the result. The results showed that compared with the independent suspension, the hydraulically interconnected suspensions which are connected by the coordination device had better antipitch performance, as well as more stable output force characteristics. Meanwhile, the extension implementation modality of the connected device was proposed. 