Abstract: Using infrared imaging leak detection technology for large scale of SF₆ leak detection in 10 substations with different voltage levels, obtained infrared image pattern of 52 defects with different leakage position.There were corresponding leakage characteristics in different locations and family defect effect was obvious.For defect types of different leak locations, put forward the corresponding treatment advice.Finally through the case, the method of sealing with sealant was verified, which could be targeted to deal with the leak defects of SF₆ pressure gauge connection valve, pipe and other locations, improved the efficiency of live detection and maintenance.