Abstract: At present, high ground clearance sprayers are widely used in field operations. The installation of an air curtain system above the spray rod can effectively reduce the loss rate of pesticide droplets, thereby increasing the utilization rate of pesticides. Based on the CFD software, this paper uses a discrete phase model to analyze the fog droplets at different horizontal wind speeds（0 m/s, 1 m/s, 2 m/s, 3 m/s）, different nozzle upstream pressures（0.3 MPa, 0.7 MPa, 1 MPa）, and different spray nozzles. Numerical simulation of droplet loss under the application height（0.5 m, 1 m, 1.5 m, 2 m） has been carried out. The simulation results show that the droplet deposition distribution is circular without any interference. When the height is 0.5 m, Even if the horizontal wind speed is 2 m/s, the droplet loss effect is less obvious. As the horizontal wind speed and spray height increase, the droplet loss gradually increases. When the nozzle height is 2 m and the natural wind speed is 3 m/s, a part of the droplets have drifted away from the calculation area. Increasing the nozzle pressure can effectively reduce the droplet drift. The reason is that the nozzle pressure can give the droplets a larger initial velocity, and co-force the droplets to move downward to compensate for the horizontal wind speed. Lost. The air curtain structure is optimized by installing a deflector, and ANSA software is used to pre-process, fluent calculation and post-processing of the air curtain structure. The structure shows that the horizontal distribution of the outlet air flow velocity is relatively uniform, which proves that the option of installing the deflector is feasible. In the actual operation, the spraying height and pressure should be reasonably selected according to the actual situation, and the influence of the air curtain auxiliary air stream to refine the droplets and the rebound of the droplet contact leaves on the control effects of different crops should be considered.