EV SBW system structure and SBW steady-state gain for the ideal steering ratio based on two freedom degree vehicle dynamics model were established. And SBW system mathematical model and the active steering control strategy were built in Matlab/Simulink. In the active steering controll, the hub steering drive motor angle was controlled by the ideal steering ratio and dynamic fuzzy sliding mode variable structure stability control algorithm. The results of the sine-input simulation showed that the algorithm based on the ideal steering ratio can meet the requirements of vehicle front wheel angle real-time compensation so as to effectively improve vehicle driving stability.