Self operated differential pressure control valve is a kind of self operated regulating valve used in open and closed water circulation system (such as hot water heating system, air conditioning chilled water system, etc.), its function is to keep the pressure difference of controlled loop constant when there is external disturbance (pressure fluctuation of network) and internal disturbance (change of internal resistance) in the controlled loop. It is suitable for heating mode and adopts differential pressure control of double pipe system to ensure system stability, Reduce noise, balance resistance, fire network and hydraulic imbalance. Whether the network pressure fluctuates or the resistance of the controlled loop changes, the self operated differential pressure control valve can maintain a constant pressure difference between the controlled loop and the network pressure.