During the field operation of high clearance selfpropelled sprayer, due to the high ground clearance, large quality and volume of whole vehicle, leading to difficulties in line changing and transfer operations that affects the efficiency of operation. In order to improve the operating efficiency of the sprayer, a steering mechanism and hydraulic steering system was designed, a control method of four wheel steering system based on PID was also proposed. Based on the mathematical model of the full hydraulic steering system, the simulation analysis of the steering system was carried out by Matlab/Simulink, the simulation result showed that: during the four wheel steering (4WS) process, the rear wheel followed the front wheel with a hysteresis of 0.04s, the maximum angle following error was 2.82°, the error was within the allowable range of Ackermans steering theory which satisfied the steering requirements. Then based on the developed 3WPG-3000 high clearance selfpropelled sprayer, a multiwheel steering system real vehicle test platform was built, and the tracking control test of the rear wheel to the front wheel angle was carried out，the result showed that during the random steering test in the field, the maximum angle following error was 2.60°, meeting the requirements of 4WS, verification of the responsiveness, accuracy and stability of the designed multiwheel steering system. The research results provided a theoretical basis for the development of multiwheel steering system of high clearance selfpropelled sprayer.