Abstract: To promote feeding automation and industrialization, an auto-feeding system is designed and developed for management of culture and feeding by deep-water net cage. PLC is used as control core, and the start-stop of each equipment is controlled by relay contactors to realize precise feeding. We introduce the working principle and design framework of the system, describe the control circuit, working process of the system and PLC hardware structure, design the control methods of key equipments and write related control program. The results show thatat feeding transportation distance of 300 m, feeding quantity is 1 200 kgh-1, and air volume of system is 5.56 m3min-1 and air pressure of system is 49 kPa. Maximum energy consumption reaches 8.4 kWht-1 (5.0 kWht-1averagely), and breaking ratio of feed is less than 0.7% and spraying distance is 11.3 m. With this system, feeding can be carried out by dynamic timing at designated points in fixed quantity, which meets the requirement of cluster culture by deep-water net cage.