In order to achieve the transformation of China's energy structure and promote the dual carbon strategic goals, offshore wind power with large capacity and high reliability has become an important carrier to ensure the security of the energy system. The 500 kV XLPE submarine cable factory joint, as the key to achieving long-distance ocean power transmission technology, is susceptible to interface insulation breakdown due to the differences in performance before and after insulation recovery in the design structure and manufacturing process, which has become an important factor restricting the development of long-distance large-scale offshore wind power projects in China. According to the sampling test, routine test, and type test requirements for the 500 kV XLPE submarine cable system, combined with the structural design of the 500 kV XLPE submarine cable factory joint, a related parameter of the factory joint counter stress cone structure is provided, and the distribution of the factory joint test field strength is verified through simulation. Based on the influencing factors of insulation recovery in the joint manufacturing process of 500 kV XLPE submarine cable factory, this paper provides a technical analysis of its key manufacturing process.