In order to solve the problem of low loading carrying capacity, small feeding range and low feed utilization rate of the high density cultivation of the pond, an automatic feeding machine was proposed based on the principle of gas transmission. According to the working principle, the paper designed and analysed feeder system, material conveying system, polishing system and control system, using pneumatic feeding as energy, pipeline as a conveying mechanism, spreading plate as the feeding mechanism, SIEMENS S7-200 PLC as the control unit of the system. According to the requirement of feeding. At the same time, the feeding system can satisfy the feeding of the 6 groups, and can individually control to meet the demand of feeding. Feeding distance can reach 20m, the average feeding rate was 400kg/h, broken rate was lower than 0.9%. It can basically meets the design requirements. The work process show that, compared with conventional feeing machines, the automatic feeding machine had the characteristics of simple structure, convenient operation, no-easy crushing, high feed utilization rate, and can realize the precise adjustment and control of feeding amount to achieve the desired results.