This article systematically reviews the unplanned shutdown cases in ethylene plants in China from 1982 to 2023, focusing on a statistical analysis of 31 leakage-related events. Combined with typical cases of leakage that did not result in unplanned shutdown, key vulnerable points prone to leakage are identified, including hydrogen service locations, low-temperature flanges, and areas subject to two-phase flow erosion.? More targeted key protective measures are formulated for different risk characteristics, providing scientific and specific reference for leakage prevention and control management in ethylene plants.