Abstract: In order to study the effects of different plant protection machinery on the control of cotton aphid and explore the best plant protection machinery for the control of cotton aphid. In this paper,three planting protection machinery wereused: a rod sprayer,a spray gun,and a UAV to carry out pesticide application experiments in the cotton field. The controleffect of three plant protection machinery on cotton aphid was estimated with the rate of insect population decline and thecorrection conrtol efficiency. Considering the influence of the deposition effect of droplets on cotton leaves on the preventio-n and control effect of cotton aphid,the droplet deposition effect of the three plant protection machinery on cotton leaveswas comprehensively compared at the same time. Experimental results show that the overall trend of the droplet depositiondensity and coverageof three plant protection machinery on water sensitivity of paper is: the upper＞the lower,the front＞theopposite,the droplet deposition uniformity trend is: the UAV＞the rod sprayer ＞the spray gun,the front＞the opposite,the upper＞the lower,the droplets deposition distribution of the UAV on water sensitivity of paper is overall better than the other twoplant protection machinery. There were significant differences in the deposition density and coverage of the water sensitive paper of three plant protection machinery at the same site. The rod sprayer can be used for the control of explosive diseas-es and insect pests. The plant protection machinery can reach the control effect index on the 10 th day after application,a-mong which the rod sprayer is the best. The 10 th day after the application of each plant protection machinery,there was n-o significant difference in their correction control efficiency on cotton aphid,and the UAV could save 60 times of water and pesticide than the other two plant protection machinery. The results of this study can be used as a reference for the a-pplication of plant protection machinery and the selection of operating conditions in the cotton fields.