Traditional sliding mode control is prone to chattering，which affects the stability of the differential control system of electric vehicle driven by in-wheel motor. A new electronic differential controller design method based on synergetic control theory is proposed for the vehicle′s eight-degree-of-freedom dynamic model to solve the chattering phenomenon in the control process. This method takes torque as the control target, and by constructing a generalized variable about the slip ratio, the controller converges exponentially to the optimal slip ratio point. The MATLAB/Simulink simulation results show that the new electronic differential controller has the advantages of fast dynamic response, smoothness, and good steady-state characteristics.