Abstract: A machine vision and fuzzy control based spray system, which could perform site-specific pesticide application, was developed and tested for the study on Variable Rate Technology(VRT). The system could integrate information of the tree canopy with the distance between the tree and the nozzles to judge the tree size, and then to select different nozzle groups, as well as to control the flow rate and spraying range. In this way, an intelligent chemical delivery was achieved. Compared with traditional methods, the system could greatly save pesticide.