Abnormal vehicle shaking will seriously affect the passenger’s riding comfort. In order to solve the problem of abnormal tail-car shaking of 160 km/h centralized power EMU passing through the tunnel, the characteristics of tail-car vibration, the trend of external pressure difference and the transmission characteristics of suspension vibration were analyzed through line test, and the main influencing factors were determined. In order to further study the mechanism of this phenomenon, a vehicle system dynamics model containing nonlinear suspension elements was established, the actual performance of suspension elements under different body motion states and the influence of different performance on the body modes were analyzed, and the phenomenon was suppressed by some means. The results show that when the tail car passes through the curve, the shaking mode of the car body changes under the action of the lateral stop, and the coupling with the air turbulence outside the car when passing through the single-line tunnel is the root cause of the abnormal shaking of the car body. By adjusting the suspension of the second series, the abnormal rocking phenomenon can be effectively suppressed, and the dynamic stability of the rear control car can be greatly improved.