Abstract: The nonconcentricity of the bearing housings is an important parameter that influences the vibration characteristics of the bearing-rotor system. In this paper, a rotor supported by deep groove ball bearings is selected as the research object. The load and deformation of the rolling element and the raceways of the deep groove ball bearing are analyzed, and the bending deformation of the rotor is studied as well. An analytical model is established for calculating the added moment that is imposed on the rotor due to the bearing housing nonconcentricity. By altering the transfer matrix method, an analytical vibration model with considering the influences of nonconcentricity of bearing housings is developed for the rolling element bearing-rotor system. On the basis of this vibration model, a rolling element bearing-rotor system example is computed numerically for analyzing the influences of nonconcentricity of the bearing housings on the vibration characteristics of the targeting system. A series of regular curves are obtained. The calculation results indicate that the critical speed of the rotor system increases gradually with the misalignment under a given load. The amplitude of unbalance response of the system and the position of the peak amplitude vary with the misalignment, leading to a variation of the vibration type of the rotor system from symmetric to asymmetric.