The utility model discloses a net cage system for breeding siganus. Placing in aquaculture sea area, the device comprises a culture net cage, a plurality of fry collecting net cages and trapping net cages, the fry collecting net cage is arranged outside the culture net cage; fish luring feed is arranged in the fry collecting net cage, the trapping net cage is arranged in the aquaculture net cage,the three corners of the top of the trapping net cage are pulled to a frame fixedly connected to the top of the aquaculture net cage through pull ropes respectively, half of the trapping net cage is exposed out of the water surface, and the other corner of the trapping net cage is tied with a pull rope and a pendant and then sinks into water. By the adoption of the net cage system, seedlings can be collected on site, transportation stress is reduced while the seedling purchasing cost is saved, the seedlings do not need to adapt, and the survival rate is high. Meanwhile, fishing can be realizedby lifting the trapping net cage. The system can achieve uninterrupted fry throwing and big fish catching, the aquaculture net cage achieves circulating aquaculture, efficient utilization is achieved, and benefits are good.