In order to investigate the effect of airflow vortex operation on the droplets size distribution of aerial spray, the XR-Teejet 110015 pressure fanshaped nozzle was used as an example, and was tested in the wind tunnel and field respectively. The wind speed in the field was simulated by the airflow velocity of the wind tunnel test, and three spray pressures were set, the droplet size were measured by the laser particle size analyzer. In the field experiment, a fourrotor unmanned aerial vehicle (UAV) was used as the platform to spray on target, then the droplet size distribution regular of each vortex shape formed by different interaction between rotor airflow and canopy were analyzed. The results showed that under the conditions of wind tunnel, each test nozzle was in a very fine atomization level, and the atomization performance was well and stable. The formation of vortex state had a significant effect on the droplets size distribution in the field test. Under the three vortex states, the comprehensive average proportion of droplet size less than 200μm was 73.52%, 74.21% and 84.20%, respectively, which was consistent with the wind tunnel test results, but the DV01, DV05 and DV09 of the droplet in the field test were significantly higher than that in the wind tunnel test. The droplets size of the obvious vortex state and small range vortex had a relatively flat distribution trend in the various layers of the crop, and the variation coefficient of volume median diameter in each layer was between 3.96% and 10.66%, but the no vortex state showed a large volatility, and the coefficient of variation was in the range of 9.49%~17.11%, which indicated that the relatively obvious vortex state was conducive to the penetration of droplets in the vertical space and achieved better application effect. The research results can provide reference and guidance for the accurate spraying operation of agricultural UAV, and have important significance for improving the utilization rate of pesticides in aerial spraying operations.