An accurate modeling method for electric parameters prediction of CSR (Contactless Slip Ring) is proposed in this paper. Parameters of CSR can be conveniently obtained before simulation and prototype design. In order to increase the accuracy of the predicted electric parameters, the main flux are corrected by taking the partially coupled flux into account, and the leakage inductance is obtained by a novel method taking use of the limit calculation. Formulas for parameters prediction are derived. The prediction values approximates the FEM (Finite Element Method) values accurately. Furthermore, a prototype is designed to verify the proposed method.