The invention relates to a hot-rolling seamless tube sizing roller cooling water ring. The cooling water ring comprises cooling water ring bodies, and the cooling water ring bodies are movably arranged in gaps between adjacent roller racks; each cooling water ring body is composed of a water ring, a water inlet pipe, a first supporting rod and a second supporting rod, one end of the water ring isconnected with the horizontal water inlet pipe, and the water inlet pipe is connected with an external water pipe through a quick joint; multiple nozzles are uniformly arranged at the portion, corresponding to rollers at the two sides, in the circumferential direction of the water rings, and the number of the nozzles is the multiple of 3; the first supporting rods are arranged on the water rings,the second supporting rods are arranged on the water inlet pipes, and the first supporting rods and the second supporting rods achieve height-direction and radial-direction supporting and locating effects on the cooling water ring bodies. According to the hot-rolling seamless tube sizing roller cooling water ring, the movable cooling water ring bodies are adopted, configuration is conducted according to the using requirement, the number of configured and maintained racks is reduced, the situation that the cooling water ring is damaged when a roller rack is frequently overhauled is avoided, andthe water cooling effect is guaranteed.