Aiming to clarify the transmission relationship of the crossed friction wheel mechanism and apply it to the motion analysis of the Mecanum wheeled omnidirectional mobile car, the transmission principle was theoretically analyzed through motion analysis and force analysis. The theoretical relationship and the design calculation method of dynamic parameters of a special case of the crossed friction drive about wheel-ground crossed friction wheel drive were analyzed. The method for judging the axial movement direction of the driven transmission member was constructed. The ADAMS was used to simulate the transmission model of crossed friction wheel under different loading conditions. On this basis, the motion principle of the omnidirectional mobile car based on the Mecanum wheel was analyzed by using the mechanism of the crossed friction wheel transmission. The research result showed that the theoretical analysis of the transmission relationship was correct. When the transmission was effective, the angle between the static friction force of the contact point and the axis of the wheel was depended on the applied load value. The static friction of the contact point and the applied load could be adaptively balanced. The relationship between the moving speed of the wheel center and the axial moving speed along the shaft and the driving speed of the supporting shaft was not affected by the external load. These three speeds formed a rightangled triangle relationship, and the two speeds of the friction wheel were the cosine and sine of the driving speed. The transmission relationship between the ground and the small rollers of the Mecanum wheel belonged to the crossed friction wheel drive. It was feasible to analyze the omnidirectional mobile car by using theoretical movement relationship of the crossed friction wheel. It provided an intuitive and concise theoretical method for the analysis of the omnidirectional mobile car based on Mecanum wheel, and also provided a theoretical basis for the application design and analysis of the crossed friction wheel drive. 