Abstract: The operation of infrared detecting system for automatic target orchard sprayer was hard to work well in rough environment interference resulted from crucial designed defects, including short detectable distance, complex circuit, and high cost of the automatic target detector. An infrared detecting system consisting of integrated circuit for orchard automatic target sprayer was developed. Test results showed that this system satisfied in detail the design requirements of stability, sensibility, compact volume and anti-interference from environmental ray, and the detectable distance between the detector and the targets was variable from 0 to 6.15 meters, and the space between two spraying targets was no more than 0.3 meter.