Abstract-This paper presents research in steering control techniques for an automated all-terrain vehicle (ATV). According to steering wheel angle and Gas or Break Pedal, the proposed fuzzy inference logic can provide needed assist to the left and right motor position which controls the position of build-in proportional valve. Position valve increase or decrease the fluid velocity which increase or decrease the hydraulic motor speed and vehicle speed .different speed for left and right motor cause turn left or right. Under experts' knowledge of fuzzy control, the electro-Hydraulic power steering system can satisfy smooth turning left or right. Modeling and Experimental results demonstrate that the proposed method is reasonable and feasible.