Abstract: The precision pesticide application system was briefly introduced, which could reduce the impact of pesticides on environments, increase the ecosystem sustainability, and protect the operators. The tree image processing, tree crown recognition and spray execution system was included in the system. The tree image processing system includes a CCD camera, an image grabber, a computer and software, and an experimental set-up. The software was developed to realize the functions as follows: capturing, extracting and processing the key frame of tree image from video stream, segmenting the green target from its background by relative color indices, measuring the segmented image to obtain morphological and location features of the target. The spray execution system composed of spraying table, nozzles, solenoid valves and relays was developed, which would realize the data communications and convert spraying decision making results to instructions for controlling the spray execution system. The results of experiments showed that the developed systems were practical and suitable to recognize the tree images and the tree crown types. The non-target or off-target pesticide contamination could be decreased through precisely spraying the pesticide on the desired target tree.