Abstract: In order to reduce labor cost and feed cost in factory aquaculture process, this paper designs a kind of Siemens S7-200PLC-based rail-type automatic feeding system of factory aquaculture. This system has its own power source for power supply; while it operates on H-type steel rail above fishponds in high-temperature and high-humidity factory aquaculture workshop, it can suppress the interference which the relevant cultivation equipments in workshop cause on automatic feeding system and realize accurate positioning, precise feeding, and recording and storage of feeding data for fishponds in factory aquaculture workshop. The operation result via preliminary experiment shows that the rail -type automatic feeding system of factory aquaculture can operate stably, with a travelling speed of 10-13 m/min and feeding accuracy above 95.8%, and the maximum deviation of positioning accuracy is 43 mm, thus this system meets the design requirements of initial scheme.