Based on the analysis of the rolling bearing vibration, this paper expounds that cylindrical roller bearing′s contact vibration and radial stiffness change exist essencical correlation under the fixed radial load condition, bearing′s radial stiffness with roller′s position change and change. With cylindrical roller bearing NU306ECP, for example, using ANSYS software to create the model of single roller in contact and calculate radial deformation in the allowable stress range with the radial load increasing． Using Matlab software for programming and polynomial fitting, this can get functional relationship between load and deformation. The function relationship is applied to analyze bearing′s radial displacement in the state of odd pressure and even pressure under the radial load condition. The results show that with the increasing of the load, bearing′s variation of radial displacement occur fluctuation.