Abstract: A device for cooperatively treating aquaculture tail water by algae and bacteria is provided, including an aquaculture part; the aquaculture part is communicated with a sewage discharge part, and the sewage discharge part is communicated with a tail water treatment part, and the tail water treatment part is communicated with the aquaculture part; the sewage discharge part includes a sewage pipe communicated with the aquaculture part, where one end of the sewage pipe away from the aquaculture part is communicated with the tail water treatment part, and a sewage pump is arranged on the sewage pipe; the tail water treatment part includes a second shell, a bottom end of the second shell is communicated with the sewage pipe, a top end of a side wall of the second shell is communicated with the aquaculture part, several guide plates are arranged in the second shell.