Abstract: Operating parameters of UAV are very important to spray effect, and different operating parameters should be set according to the control requirements of different crops and pests. In this paper,by analyzing the force condition of fog droplets, according to its force equation,it can be known that its flying speed and height are important factors affecting the deposition effect of fog droplets. In this experiment,the water-sensitive test paper was used to detect the deposition effect of wheat spray droplets at different flight speeds and altitudes, and the SPSS software was used to compare and analyze the relevant data, so as to determine the best operating parameters of UAV for wheat control. The results show that the droplet deposition effect of UAV is the best when the flight speed is 4m/s and the working height is 2m,which provides theoretical and practical reference for setting the best operating parameters when using UAV to control wheat.