Abstract: In order to improve the quasi-determination of electrical fault diagnosis of high-voltage equipment, according to the actual situation of the power supply company in BX region, this paper summarizes the geological, geographical and environmental characteristics of the region, analyzes the negative impact of the environment on high-voltage electrical equipment, and puts forward relevant improvement measures. Through the case study of electrical fault of high-voltage equipment, the fault diagnosis test project is studied. To reduce the environmental impact of high voltage electrical equipment failure. On the basis of the existing fault diagnosis test projects of high voltage equipment in this region, the improvement measures are proposed to increase the online monitoring, carry out targeted diagnosis and analysis of equipment environment based on the fault type, and prioritize the test projects that determine the fault caused by the environment.