In order to improve the pesticide application efficiency and reduce the agricultural chemicals lost in orchard spraying, an automatic target spraying system based on the 3WGZ-500 selfpropelled sprayer was designed in view of excess spraying and ineffective spray at fruit trees clearances during traditional spray operation. Ten ultrasonic sensors were fixed on the two sides of the orchard sprayer at 15° intervals, which were used to measure the distance between the nozzles and sprayer targets. The sensor measure range was 0.35~2m and emission angle was 60°. Based on the sensor signals, three channel solenoid valves by side were used to control the switch of nozzles at the corresponding position. The experiment was worked at the five years old apple orchard, test spray pressure was 0.5MPa and operating speed was 1.3km/h, 1.7km/h, 4.5km/h and 7.2km/h respectively. The result showed that the operating speed had little effect on pesticide application efficiency at the condition of with target spraying system and without target spraying system. This target spraying system can reduce unnecessary spraying chemical pesticides. The pesticide application efficiency was 35.8% with target spraying system, which increased 29.7% compared to without target spraying system’s 27.6% and increased 91.4% compared with traditional spray’s 18.7%. The system can effectively reduce the pollution to the environment. Ground loss rate at different operating speeds was proximity. The ground loss rate was 13.3% with target spraying system, which reduced by 42% compared to without target spraying system’s18.86%.