Driving axle of a light bus is tested on bench, and the reasons of abnormal vibration and noise are analyzed. 3D model is established by the method of reverse engineering and modal analysis is done by the method of finite element analysis. Finite element model is verified by modal test. Improvement measures are proposed according to oversized impacting of the hypoid gear pair, resonated rear axle housing and resonated rear cover, which are verified through the bench test. The results show that vibration and noise reduced significantly. Those improvement measures are proved practical and effective.