In order to early find inner component loose of GIS and to aviod the occurrence of serious accidents such as parcial discharge and inner breakdown

the paper studies a method which can make online detections and diagnosis for inner component loose of GIS with ultrasonic method and ultra high frequency method（UHF）

and proposes the detailed detection steps: firstly

detect the key position of GIS using ultrasound method by cycle;then detect the ultrasonic signal abnormal using UHF method

finally

contrast and analyze the maximum amplitude position detected by ultrasound method and the internal structure chart

determine the loose parts.At last

cases show that the method is effective.