In view of the mechanized plant protection wilt prevention and control problem, DJI 8 rotor UAV, 3WX-2000G stretcher sprayer 2 planting sand melon field spray test, comparison analyzed the influence of different application technology and tools on the droplet deposition distribution law, for the pest control requirements and application technology of plant protection tools. The test results show that the plant protection UAV pharmaceutical operation, due to the rotor airflow disturbance, the leaves in the sand melon, stretcher spray on the front of the blade has more droplet deposition, the back of the front deposition becomes less, thus increasing the effect of the wind field on the back of the blade. In terms of fog droplet density and coverage, there is no obvious difference in the UAV spray droplet density before and after the addition of additives, mainly because the crop leaves are hydrophilic, and in the hydrophilic crops, the addition of wet spreading agent when the spray has no obvious effect on its spray deposition effect. From the size of the fog droplets deposited on the water-sensitive paper, the stretcher sprayer on the front of the blade is significantly larger than that of the drone, while the difference on the back of the blade is smaller. The fog droplet density and coverage of plant protection UAV are less than the vehicle stretcher motorized sprayer, but the average droplet density on the front of the blade is 18 / cm2 and 14 / cm2, which is effective fog droplet density; adopt ST10001 nozzle, flight altitude of 3.5m and obtain optimal deposition distribution at flight speed of 3 m/s.