The invention discloses a catching net cage for purse net aquiculture, which is characterized in that the catching net cage comprises a barrel-shaped frame, a classification gate and a netting, wherein the classification grate is arranged on the side of the frame and consists of a plurality of grids in parallel; gaps for fish less than certain body width escaping from the net cage are formed among the grids; the netting comprises a first netting, a second netting and a third netting; the first netting and the second netting are arranged at the top and bottom of the frame; and the third netting is arranged on the side face of the frame by an opening-closing mechanism in an opening and closing manner. Compared with the prior art, the net cage has the advantages that the net cage adopts an opening-closing device to catch large fish and release small fish according to the relation between the weight and body width of the fish and the fish evading behavior, and the fish can be classified while the catching is finished.