To clarify the mechanism of the crossed friction wheel drive， the motion and the force relationship between the driven friction wheel and the active friction wheel are constructed by using the mechanics theory. The two basic forms of theoretical calculation method about the axial displacement are established. The basic form is a driven friction wheel along its own support axis direction， and the other is along the support axis direction of the active friction wheel. The judgment method of the movement direction is established completely. The two basic forms of crossed friction wheel drive model are simulated by ADAMS. On this basis， using the principle of the crossed friction wheel drive， the corresponding relationship between the ten classic cases applied in engineering and the two basic forms of the crossed friction wheel transmission mechanism is analyzed， and the characteristics of the institution is summarized. The research shows that the theoretical design calculation method is accurate. It provides a theoretical basis for the application design and analysis of the crossed friction wheel drive.