In order to explore the effect of spray droplet deposition and applications of multi-rotor unmanned aerial vehi-cle at late rice growth, spray test was done at different working heights. We used droplets test card receive droplets, and according to the different working height, three groups of experiment to be designed, respectively is 3 meters, 4 meters and 5 meters. The analysis results showed that: In different working height, droplets in rice canopy and lower level had different sedimentary effect, and the distribution uniformity coefficient of variation was also different. The total quantity of droplet deposition at the targets reached minimum when the working height was 5 meters. Meanwhile, canopy and the lower blade had a largest coefficient of variation value of 92 . 11%, 150 . 29%. The total quantity of droplet deposition at the targets reached maximum when the working height was 3 meters. Meanwhile, canopy and the lower blade had a smal-lest coefficient of variation value of 32 . 94%,49 . 47%. Three groups of tests showed height showed droplet deposition of rice was higher than the lower blade, blade side is higher than another side. The research also has a significance in rea-sonably spraying pesticide, increase rice production and improving the efficiency of spraying.