According to the requirement of LPG tank car inner wall cleaning,a wall-climbing jet cleaning trolley was designed,which combined high-pressure water jet and mechanical brushing. By establishing the static and dynamic model of car wall cleaning,the minimum adsorption force equation for reliable adsorption of car and the minimum driving force equation for stable operation and steering of car were derived. The example analysis under different wall inclination angles shows that the main instability form of static adsorption is wall sliding,and the minimum adsorption force is 51. 8 N when the wall inclination angle is120 degrees. The main instability form of stable operation is differential steering,and the minimum driving torque is 2. 95 N·m when the wall inclination angle is 50 degrees. The prototype experiment proves that the research results are reliable,which provides a theoretical basis for the development of LPG tank car automatic cleaning equipment and the corresponding technical research.