Abstract: Flight height and flight speed of the UAVs were used as test factors.Effects of 6 different test factors combinations about flight height and flight speed on the two test indexes（coverage density of droplets and coverage uniformity of droplets）were studied.Test results showed that under different test factors combinations，coverage density of droplets at different sampling points and coverage uniformity of droplets at each sampling zone was obtained.The overall change of coverage density of droplets ranged from 3.71-63.29 drop/cm2；and the overall change of coverage uniformity of droplets ranged from 24.65%-49.1%.When flight height was 1.5 m and flight speed was 4 or 5 m/s，two test indexes（coverage density of droplets and coverage uniformity of droplets）showed the optimal state.Through variance analysis，effects of flight height on coverage density of droplets and coverage uniformity of droplets were extremely significant（P＜0.01），effects of flight speed on coverage density of droplets and coverage uniformity of droplets were significant（P＜0.05）.By Duncan′s multiple range tests，significant differences in every test index from each group were analyzed（P＜0.05）.