The common-mode voltage brought by PWM variable frequency power supply to the motor is the main cause of bearing corrosion, and the shaft current is an important parameter for evaluating the bearing corrosion, and its calculation accuracy largely depends on the calculation accuracy of the high-frequency parasitic capacitance of the motor. This article starts from the structure of the stator winding of the motor, according to the relevant basic theory, derives the formula for calculating the high-frequency parasitic capacitance of the stator winding, then a high-frequency equivalent circuit parameter model of the motor stator winding is obtained, and the three-dimensional motor model is established for simulation calculation. Taking a certain type of motor as an example, the capacitance parameters are measured, and the theoretical calculation and simulation results are compared and analyzed with the measured results to verify the accuracy of the theoretical calculation and simulation analysis. A high-frequency equivalent circuit parameter model of the motor stator winding suitable for practical engineering applications is obtained, which provides relevant technical support for quantitatively evaluating the shaft current of the variable frequency power supply motor in the future.