Abstract: High-voltage bushings are crucial in power systems, mainly used for insulating, protecting and supporting high-voltage conductors in power equipment. This paper introduces an abnormal fracture fault case of high-voltage bushings. Through protection operation analysis, disintegration inspection, factory return testing and relevant experiments, the fracture causes are comprehensively analyzed. Targeted preventive measures and reference suggestions are also proposed for the same type of in-service high-voltage bushings.