Abstract: Under the national double carbon strategy, cross-linked polyethylene (XLPE) insulated cables are difficult to meet the needs of green and sustainable development, and the development of alternative thermoplastic insulation materials has become an important direction. Polypropylene (PP) material, with its excellent electrical insulation properties, heat resistance, and environmentally friendly advantages of being recyclable by melting, has become a core research focus in the field of eco-friendly power cable insulation materials. However, during the production process, the insulation layer of polypropylene insulated cables is prone to white ring phenomenon, which reduces the mechanical strength of insulation material and affects the overall performance and service life of cables. In response to this issue, a mold was designed to reproduce white ring phenomenon in the production process of polypropylene insulated cables to analyze the causes of white ring phenomenon, and by improving the cooling process, this problem was successfully improved, which provided a strong technical guarantee for the green and efficient production of polypropylene cables.