ANSYS has no module to analyze dynamics of electric machine rotor, especially to calculate critical speeds. But it has element types, such as beam element and matrix27 element, which can be modeled as stiffness, damping and mass matrix. In this paper, Beam4 element and matrix27 element are adopted to model the shaft and bearings, respectively. Some ideas are presented to deal with critical speeds calculation using ANSYS. To verify the validity of the method, an example is given to show the procedure of critical speeds calculation. Also, the analysis results obtained from ANSYS reach a good agreement with those calculated by DyRoBeS software and testing results.