Abstract: The motion of the wheel under time-varying loads on the rough horizontal plane was discussed, in which both sliding and rolling frictions were considered. The results show that the wheel can exhibit 9 different motion modes. The load requirements of keeping different motion modes were shown. Using the concept of phase space, the relationship between motion modes and loads was described by a phase diagram, in which the force and moment are regarded as state variables, and the transformation of the motion modes according to the loads were revealed. Then based on the phase diagram, the load path can be plotted in the diagram, by which the displacement of wheel center as a function of time can be calculated by integral. Taking a competition question as an example, the load path was plotted with dimensionless parameters, and the effects of load position and friction on the motion of the wheel were analyzed. The analysis method solves the scientific problem of analyzing the forces and motion of a circular wheel on a rough horizontal surface.