Hydraulic control valve is a kind of automatic control valve which opens and closes and regulates by utilizing the medium's own pressure, and is widely used in urban water supply and drainage system, fire-fighting water supply, industrial circulating water and water supply of high-rise buildings and other working conditions. The valve can be operated without external power, and is suitable for a variety of media such as clean water, weak acid and alkaline water, seawater and so on. According to different functions, it can be equipped with a variety of control accessories, such as pressure reduction, pressure holding, pressure relief, slow closure check, flow control, etc., to realize the effect of pressure stabilization, waterproof hammer, energy saving, and prolonging the life of pipeline network and equipment. Hydraulic control valves have compact structure, sensitive response, reliable sealing, and can maintain stable operation under complex working conditions, which is the indispensable core equipment in modern fluid control system.