As an excellent insulating and arc-extinguishing medium, sulfur hexafluoride gas has been widely used in the field of high-voltage electrical appliances. The failure of traditional transformer oil current transformer and voltage transformer often causes violent explosion, which is very destructive, while sulfur hexafluoride insulation equipment does not have this defect. Because sulfur hexafluoride gas has these advantages, sulfur hexafluoride circuit breaker completely replaces the traditional oil switch, and sulfur hexafluoride current transformer and voltage transformer have also been widely used. SF6 equipment is small, reliable and stable, and the most worrying problem is the leakage of SF6 gas. Under normal circumstances, the concentration of moisture in the atmosphere is dozens of times that in SF6 gas chamber. In these areas with relatively high humidity in the south, the difference of moisture concentration may reach hundreds of times. Therefore, the huge difference between internal and external concentration makes moisture penetrate into SF6 gas chamber whenever there is a chance of equipment leakage, causing a sharp increase in micro-water. However, under the action of electric arc and high temperature, moisture will produce a series of reactions with SF6 gas, and moisture is the main promoter of corrosiveness and toxicity. Therefore, leakage is one of the important causes of SF6 electrical equipment failure. There are many methods for SF6 gas leakage detection of power equipment, such as soap water leak detection, packing leak detection, hand-held leak detector leak detection and so on, but these methods are very intensive, and the most important thing is that they can't detect the state in real time. According to the requirements of "Preventive Test Regulations for Power Equipment Handover", sulfur hexafluoride gas leak detection project must be carried out during handover and after overhaul of sulfur hexafluoride electrical equipment. Because the traditional detection method is time-consuming and labor-consuming, and its efficiency is low, it is difficult to comprehensively detect the leakage of a large number of newly handed-over sulfur hexafluoride electrical equipment. Even for the equipment that knows obvious leakage, there is nothing to be done because of the low-level detection method, and the air chamber can only be guaranteed to reach the rated pressure through continuous air supply. By using SF6 gas imager, the leakage of SF6 electrical equipment can be easily and quickly detected anytime and anywhere, which not only improves the pertinence of maintenance, but also saves a lot of manpower, material resources and financial resources, and also ensures the safe operation of electrical equipment, which is of great significance to the safe operation of the whole power grid.