In order to solve the problems of great labor intensity, low feeding accuracy, nonuniform, etc. in industrial aquaculture, a rail-type automatic feeding system based on the PLC was studied and designed. The system is composed of 4 parts including loading device, traveling device, feeding device and    control device. The control part of the system takes PLC as the core and touch screen as the human- machine inter-face, where it uses low pressure pneumatic conveying way to load baits, drives the       walking car to convey baits, using the spiral feeding device and the rotating disc to throw baits evenly and quantitatively. The test results showed that: Feeding in 4 aquaculture ponds can be realized, feeding time is set at 6 times, running speed is up to 18.75m/min, feeding accuracy is 0.5%~2.2%, feeding     speed is about 1kg/min, and the positioning accuracy is around 110mm. The feeding system is high in  precision, uniform in feeding, and high in efficiency, which can effectively improve the feed efficiency  and reduce labor intensity, thereby reducing the costs of industrial aquaculture.