A kind of Hilly power chassis with variable ground clearance and wheel track (VII-HPC) was designed to adapt to hilly terrain and agronomic characteristics of various types of crops. Hydraulic four wheel steering scheme without steering trapezoid has been proposed. To reduce turning radius and achieve same rut steering, the steering strategies are two ipsilateral wheels steering with a reverse and equal angle. The displacement relationship of right and left steering cylinder would be optimized by genetic algorithm to achieve Ackermann steering. The rotation of the steering wheel is not too large to avoid movement interference, which the minimum turning radius of the same wheelbase ordinary tractor was provided a reference. After change ground clearance, the wheel deflected around the kingpin. The relationship between the effective turning angle in the horizontal plane and the displacement of cylinder should be redefined according to the geometric relation. The conditions to meet the Ackermann steering need to be re-discussed because the wheelbase and track of the chassis would be altered after VII-HPC change ground clearance and the track. Experimental results show that the structure of steering system and steering strategy is reasonable and feasible.