The sealed self-retracting lifeline is a high-altitude fall protection product specially developed for the offshore wind turbine operation and maintenance technicians. When the O&M technicians are working at heights, they must wear a full-body special safety harness, and the D-shackle on the back and the safety hook of the self-retracting lifeline are connected to provide safety protection when the operator accidentally falls. The whole device adopts full seal design to effectively prevent the corrosion of the product in the harsh environment, and the safety performance is great.