The vibration of railway wagons bearing is an important comprehensive quality index, which directly affects the quality and service life of bearing products. In this paper, the model of double row tapered roller bearing is established based on the method of dynamics to low vibration. The structure of bearing is designed optimally and the original and optimal comparison experiments and vibration characteristics are developed and analyzed respectively, and the accuracy of theory and structural optimization is verified. It is concluded that the bearing dynamics model is verified. In addition, the bearing vibration is reduced through structural optimization.