Abstract: Involving power system, transmission system and suspension system, the vehicle vibration and noise control is a comprehensive project. The abnormal vibration of a bus is associated with noise when the speed ranges 95km/h―120km/h. Both fixed sampling and order tracking sampling are used in this paper to carry on road tests. Via order tracking and job deformation analysis, combined with partial natural frequency test and spectral analysis, the 11Hz―15Hz cycle excitation of wheels is identified to be the cause of abnormal vibration, because it is close to one of the modal frequencies of the vehicle body. Finally, reasonable measures are suggested to reduce the abnormal vibration of the vehicle body.