A46 pilot operated safety relief valve is a novel structure of safety relief valve. It is mainly used in the fields of petroleum and natural gas, chemical industry, electric power, metallurgy and city gas, etc. It is an overpressure protection device for pressurized equipment, container or pipeline. Its main advantage is to change the direct action of the spring to the indirect action of the pilot valve. It improves the sensitivity of action, and the main valve adopts sleeve piston type, with high accuracy of action, good repeatability, high return pressure, good sealing performance, capable of discharging with high backpressure, stable and reliable operation, on-line calibration, and convenient operation and maintenance.