Abstract: A remote control boom sprayer was developed using a four-wheel steering hydraulic chassis with high-clearance, to meet the requirement of disease and insect pest control of vegetable planting in the field. A PID control algorithm was used to design a hydraulic power system and variable spraying system. The hydraulic power system calculated wheel slip rate by comparing actual speed and wheel speed in real time, to take ideal slip rate as the control target for real-time power distribution. The variable spraying system converted target flow rate according to actual speed in real time and target spray volume per unit area to adjust spray flow rate in real time with target flow rate as the control target. The results showed that the left front wheel had the largest slip rate with an average slip rate of 6.14%, which could be stable within ideal range of slip rate. The wheel with the smallest slip rate was the left rear wheel, which was the wheel with the largest load. The average slip rate was 0.76%, significantly smaller than other wheels. The average droplet deposition rate was 93.4%, and the coefficient of variation was 21.6%. The variable application system had excellent adjustment ability with increasing speed, but spray quality decreased slightly with increase in speed. The sprayer could provide reference for the development of intelligent plant protection machinery for vegetable planting.