Abstract: To meet the centralized transmission demands of 800-1200 MW offshore wind farms, a three-core 500 kV lightweight cross-linked polyethylene (XLPE) insulated AC submarine cable suitable for 200-meter water depth has been developed. The insulation thickness of the cable was verified through analytical calculations, and its current-carrying capacity under various installation conditions was validated using COMSOL finite element analysis (FEA) software. Additionally, optimizations were made to the long-length insulation extrusion process and the integrated large-section cabling and fiber optic composite technology. Type tests and pre-qualification extended tests were conducted in accordance with relevant standards. Results demonstrate that the cable meets the requirements for industrial application in terms of lightweight design, current-carrying performance, and system reliability, providing technical support for future design and manufacturing of 500 kV and lower voltage-level submarine cables.