Abstract: In view of the problems such as the low degree of automation of the existing high gap plant protection machinery in China and the poor uniformity of application, according to the composition and technical requirements of the spray system of the high gap plant protection machine, the modular precision spray control valve group is designed, and the size parameters of the valve body module such as the valve body structure and the switching valve, pressure limiting valve, flow control valve, and section switch valve are determined through analysis and calculation. Precision spray controller can read the output signal of the pressure sensor in real time and process it, compare it with the flow instruction input of the host computer, and send the control signal to the motor driver to control the operating state of the motor to adjust the valve opening, and then adjust the total flow of the spray system, the design of the precision spray control valve group can achieve automatic adjustment of pressure and flow, spray rod segmented independent control and parameter real-time feedback and other functions. The experimental results show that the spray system pressure and the actual flow rate approximately meet the linear relationship, the coefficient of fit is 0.997 5, the flow value is in the range of 0-50 L/min, the average relative fit error is 1.7%, and the calibration accuracy can meet the control requirements. The maximum flow rate that can be adjusted by the precision spray control valve group is 40 L/min, and the actual flow rate of the valve changes evenly during the effective stroke of the valve, which is in line with the linear flow characteristic curve relationship. The study can provide a reference for the precision spray control strategy of the high gap plant protection machine.