Abstract: Abstract: In order to meet the feeding needs of industrialization aquaculture system, an automatic feeding system was designed and developed applying the monorail technique, the slide rail power supply technique, the ultrasonic positioning technique, the wireless communication technique and the computer software technique. The system was composed of a running system, a power supply system, a feeding equipment and a control system. The feeding system with the function of auto detecting and error alarm could be automatic start and stop, weigh feeding amount and record system operation and feeding data automatically. The running system was mainly composed of a monorail likes a raceway made by H-shape steel, an electric pulley block and an ultrasonic positioning sensor. The four T forging steel rail wheels of the electric pulley block ran on the lower wing plate of H-shape steel. One reflecting plate (80 mm×150 mm) was installed on the monorail corresponded to each rearing tank. The number of each rearing tank was identified by the different distance between each reflecting plate and ultrasonic sensor moving with the electric pulley block. The feeding device comprised a hopper, stepper motor, a gate and four weighing sensors. Four sensors hung up the hopper to the electric pulley block and weighed the mount of the hopper. Opening and closing of the gate was controlled by the changes of the hopper weight. The design calculation showed that when using HW100×100 steel monorail, with the diameter of 0.06 m T forging steel rail wheels, gear ratio 20:1 gear transmission group and 24 V DC motor to drive the system to moving on the monorail, the motor power must be more than 0.2 kW, speed was 2 000 r/min, output torque requirements must be over 0.58 N·m. The automatic feeding system prototype was designed by Solidworks, and the prototype was tested for the feeding amount accuracy and positioning deviation. The experiments showed that the feeding system was reliable and accurate for feeding with travelling speed 19 m/min, positioning accuracy was in the range of 58-118 mm, bullet storage capacity was 20 kg, feeding capacity was 3 kg/min and feeding accuracy was in the range of 0.5%-2.2%. The system effectively improves the feeding accuracy, reduces the feed waste, abates the labor intensity, and meets the needs of industrialization aquaculture system at the direction of the mechanization and automation. Future improvement will include a smoother monorail without seams and speeding the response of the electrical components to improve the accuracy of feeding and positioning. The results of this research provide a reference for the automatic feeding system design and the related follow-up research.