Abstract: A new type of gas leakage detection and alarm device for GIS equipment is developed.It is installed at the flange of GIS equipment.It can accurately detect gas leakage and alarm by means of acoustooptic information.The built-in pump can suck the surrounding air through the air inlet into the detection device,and the air passes through the gas sensor on the isolation plate for analysis.If gas leakage is detected,the gas sensor transmits the detection information to A/D converter,converts analog signal to digital signal by A/D converter,and then arrives at the information analyzer after processing by MCU to analyze it.If the measurement results exceed the set threshold,the alarm system starts buzzing,and the alarm lamp flashes.Remind staff to do maintenance.