This paper has studied the variable steering ratio for steering-by-wire (SBW) based on the 29 DOF vehicle dynamic model, which kept the steering gain of vehicle constant. And the steering ratio varied with the vehicle velocity and hand wheel angles. We have proposed three control strategies for SBW including front wheel control, yaw rate feedback control and yaw rate & acceleration feedback control. We compared these three control methods by simulation and simulator tests. We have researched the forward and feedback control methods in the four wheels (4WS) for SBW system. And compared with 2WS for SBW and the classical 4WS. The results indicated that 4WS for SBW could improve the vehicle handling.Copyright © 2005 by ASME