Abstract: Coal winning machine is an crucial equipment to realize the mechanization and modernization in mine production, its running status will affect the whole coal mining efficiency. First, taking a coal winning machine as the research object, the virtual prototype model of transmission system is established in UG and the gear system is systematically analyzed in ADAMS. the gear system of coal mining machine under the normal, geometric eccentric 1 mm and geometric eccentric 2 mm fault conditions is simulated ,Then, the meshing force curves in different time and frequency domain are obtained. the results show that with the increasing of the degree of eccentric, meshing force has obvious cyclical impact in the time domain and the corresponding amplitude increases, besides, in the frequency domain meshing frequency amplitude decreases, the side band amplitude and intensity increased gradually, and use side band meshing frequency amplitude to characterise the fault degree. The results of the study provide theoretical basis for the fault diagnosis and detection.of rocker driving system of shearer.