Abstract: In order to meet centralized transmission demands of 800~1200 MW offshore wind farms, 500 kV three-core lightweight cross-linked polyethylene (XLPE) insulated AC submarine cable suitable for 200 m water depth was developed. Insulation thickness of submarine cables was verified through analytical calculations, and current-carrying capacity under various installation conditions was validated using COMSOL finite element analysis software. At the same time, long-length insulation extrusion process and large-section cable-forming optical fiber composite integration technology were optimized, type tests and pre-qualification extended electrical tests were also carried out according to relevant standards. Results showed that submarine cables could meet the requirements of industrial application in terms of lightweight design, current-carrying capacity, and system reliability, which could provide technical support for future design and manufacturing of 500 kV and lower voltage-level submarine cables.