Abstract: A lead sheath was commonly integrated into the structure of collection submarine cables for offshore wind power and was typically externally connected to offshore wind turbines. The connection section between submarine collector cables and offshore wind turbine was subjected to prolonged stress, making it prone to cracking damage in the lead sheath, which could further lead to insulation breakdown of the main cable. Through analysis of lead sheath cracking cases from the Jiangsu region, the root causes of sheath failure were investigated, and the impact of sheath cracking on the main insulation was examined. The research could provide reference for lead sheath operation and insulation failure prevention of collecting submarine cable for offshore wind power.