The invention provides a flame-retardant, environmentally-friendly and safe polyolefin sheath material. The polyolefin sheath material is prepared from the following raw materials, by weight, 20-30 parts of ethylene propylene diene monomer, 60-80 parts of high-density polyethylene, 8-10 parts of acrylonitrile-butadiene rubber, 8-10 parts of a rubber smoked sheet, 0.5-1.0 part of bisphenol A, 1-3 parts of modified tree ash, 20-30 parts of triethyl citrate, 4-6 parts of magnesium oxide, 0.5-1.0 part of molybdenum trioxide, 30-50 parts of fumed silica, 10-13 parts of nanometer calcium carbonate, 0.5-1.0 part of capsaicin, 0.1-0.3 parts of an antioxidant AW, 0.5-1.0 part of a promoter MBTS, 0.2-0.5 parts of a promoter TMTD, 0.2-0.5 parts of sulfur, 8-10 parts of decabromodiphenylethane, 12-15 parts of antimony (III) oxide and 6-8 parts of zinc borate hydrate. The polyolefin sheath material has the advantages of excellent flame retardation, very less smoke in combustion, no generation of toxic gases or corrosive gases, good low temperature resistance, good oil resistance, good abrasion resistance, and good prevention performance.