Hydraulic level control valve with automatic opening closing valve to control the water level function, suitable for industrial and mining enterprises, civil construction in various water tower (pool) automatic water supply system, and can be used for normal pressure boiler circulating water supply control valve, the valve has the advantages of small volume, convenient installation, enable high sensitivity, small head loss water hammer phenomenon, controlled by a small the floating ball can greatly improve the utilization rate for the new tower tower, due to the size of the float reduced upper left tower float free floating height required by the decrease of water tower made of dielectric rod, overcome the old floating ball valve of large volume, easy damage, low working pressure, a lot of water overflow ills, is new towers and replacing old floating ball valve suitable.