The invention discloses a cooling water pump for an internal combustion engine, which comprises a water pump housing, a rotating shaft, a cover plate and an impeller. The water pump housing is formed with a cavity, the rotating shaft is installed in the middle of the cavity through a bearing, and the impeller is installed on the rotating shaft so as to be rotatable along its own axis. , the cover plate is firmly connected to the side of the water pump housing that is formed with a cavity; the water pump housing is provided with a water inlet and a water outlet, and a partition tongue is made in the cavity near the water outlet, and a vortex chamber is made between the partition tongue and the water outlet The flow channel and the vortex flow channel are arc-shaped; the impeller includes a hub, a disc and blades, the center of the hub and the disc is fixed, and the blades are arc-shaped, and the blades are at least two and are evenly spaced around the hub. On the disc, the disc is provided with at least two openings, and the openings are arranged between the blades; the cooling water pump for internal combustion engine of the present invention reduces the volume and quality of the impeller by opening the disc, and increases the available energy in the cavity. The volume increases the flow rate of the water pump and reduces energy consumption without changing the external dimensions and interfaces of the water pump.