Abstract: In the study,the three different type of spraying machine were applied to prevent and control grassland insect pest at a large scale,the flow of medicinal solution in the process of test （constant quantity,low quantity,ultralow quantity）,spraying extent,homework efficiency,mechanical durability,difficulty of operation and the effect of preventing and curing were all determined.It will provide the suitable apparatus for preventing and control insect pest and poisonous weeds by mechanizing in the large area in the future.