Abstract: In view of the line fault event caused by the damage of a high-voltage bushing in a substation,through the inspection, test and relevant data analysis of the line bushing, it is confirmed that the main cause of the fault is a manufacturing defect in the bushing, and the follow-up measures are proposed. On this basis, the common faults and treatment methods of high-voltage casing are summarized, providing basis for daily operation and maintenance of casings.