Hydraulic drive safety valve,as executive part of safety system on well.can classify both parts of preparation valve and driver.High-pressure oil enters the empty chamber of the driver and then press the bottom spring as to open the valve,if the pressure exceed the bearing ability of wellhead assembly,by the sign past through the sensor, the control mechanism unload the pressure out of the oil cylinder,and the spring pusheds the valves stem to close the valve and wellhead assembly so as to ensure equipment safe.