The invention discloses a power cable sheath material, which comprises the following raw materials by weight: 20-50 parts of tetrapropyl fluoro elastomer, 30-60 parts of high density polyethylene, 4-16 parts of polypropylene, 1-2 parts of N,N'-m-phenylene bismaleimide, 0.2-0.6 part of cumene peroxide, 0.2-0.6 part of triallyl isocyanurate, 15-35 parts of modified silk fiber, 5-15 parts of nano titanium dioxide, 50-60 parts of white carbon black, 20-40 parts of nano calcium carbonate, 10-30 parts of calcined clay, 1-3 parts of a silane coupling agent, 0.5-1.5 parts of stearic acid, 1-2 parts of magnesium oxide, 0.4-0.9 part of simethicone, 0.4-0.9 part of PE wax, 0.2-1.2 parts of an antioxidant NBC, and 0.2-1.2 parts of an antioxidant RD. The power cable sheath material has good waterproof and thermal stability, excellent ageing resistance and no environment pollution after discarding.