The studied hydraulic hybrid vehicle was composed of the hydraulic pump, highpressure accumulator, lowpressure accumulator, switch valve and control system. The mathematical model of the hydraulic hybrid power system and the mathematical model of the displacement servo system of hydraulic pump/motor were built. The control strategy for hydraulic hybrid vehicle was proposed. The simulation and experiment to the dynamic characteristics of the hydraulic hybrid vehicle were finished. The experimental results prove that the simulation model is effective and the control strategy is reasonable.