Abstract: Based on research of new polypropylene(PP)materials, combined with operating environment, mediumvoltage PP insulated power cable suitable for 8.7/15 kV and 26/35 kV power systems was made through calculation of key parameters such as PP insulation design and insulation utilization coefficient, and was verified by tests of physical and mechanical properties, electrical properties and halogen-free and low-smoke flame-retardant properties.Results showed that insulation and shielding materials mainly composed of PP resin and toughened elastomer could meet the operating requirements of power systems of 26/35 kV and below.Compared with traditional crosslinked polyethylene insulated cables, their long-termoperating temperature could be increased to 105 ℃; Current-carrying capacity of cables during normal operation could be increased by about 9.0% in directly buried soil and by about 13.5% in air.