Abstract: This paper prepared 110 kV grafted polypropylene insulated cables using grafted polypropylene insulating materials and took them as the research object. Through thermal performance tests of insulating materials, mechanical tests before and after aging, electrical strength tests before and after aging, type tests of cable systems and current-carrying capacity tests, the feasibility of increasing the operating temperature of polypropylene insulated cables was analyzed. The results show that PP has a higher melting point and initial melting temperature, and has better aging resistance. It meets the requirements of the electrical type test when operating at 105℃. After the operating temperature of the 110 kV grafted polypropylene insulated cable with a conductor cross-sectional area of 1200 mm² is raised from 90℃ to 105℃, the current-carrying capacity can be increased by 10.2%. It has been proved that it is feasible to increase the operating temperature of 110 kV grafted polypropylene insulated cables from 90 ℃ to 105 ℃.