Abstract: At present, the common problem of the domestic highland gap sprayer is that the sprayer rod is relatively fixed and can not be adjusted flexibly according to the field working conditions. In order to solve this problem, this paper designs a kind of retractable spray rod with adjustable spray radiation. After setting the injector, the nozzle fixed on the inner and outer frame can be automatically connected by the pressure of the liquid in the tube. According to the actual application environment, different spray amplitude can be selected in a certain range for application. In this paper, 3 D software was used to establish the model and the simulation software was used to carry out finite element analysis on the spray rod, and a simple jet frame model was built, and the error measurement and analysis were carried out for the relative position of the docking device. The simulation results show that the mechanical structure of the jet frame is reasonable. The injector spoke of the spray frame can be changed accurately according to the design requirements, which provides a solution to solve some deficiencies of the spray rod of the high gap sprayer at present.