Abstract: In order to meet the current requirements of the support carrier can climb the big slope and downgrade stably for the coal mine working face of large min ing, the paper puts forward the improvement scheme of the performance of the hydraulic system of the walking vehicle in the large slope. Through the theoretical analy sis and simulation study on the load characteristics and working principle of the walking hydraulic system, the key factors affecting the climbing performance and downh ill performance of the support carrier are obtained. When the slope is required to climb 21%, the large gradient hydraulic walking system is researched and developed t hrough the comparative analysis of two proposed programs; this paper puts forward a control strategy for heavy-duty downhill of vehicles by means of analysis of vehicl e heavy-duty downhill conditions and hydraulic control methods; Through the optimization of the system on the support carrier, the results show that compared with the i mproved vehicle, the system can greatly improve the climbing ability of the vehicle and improve the stability of the heavy load and downhill speed of the support carrier.