The circulating water system for intensive aquaculture disclosed herein includes a submersible pump, an outlet tube, an outer casing tube and a deflector plate. The submersible pump is adapted for being mounted on the bottom of an aquaculture pool at a position close to the circumferential wall. The outlet tube has a tapered section sleeved onto a discharge port, while the outer casing tube is sheathed outside the outlet tube. The deflector plate is mounted laterally to the submersible pump, such that when the submersible pump is pumping water from the aquaculture pool through the discharge port, the deflector plate acts to guide the discharged water approach the circumferential wall, thereby generating a circulating swirling flow rotating in tangential direction along the circumferential wall.