The invention discloses a cable sheath material and a preparation method thereof, belonging to a cable sheath material. The invention is mainly applicable to coal mine cables. The cable sheath material comprises chlorinated polyethylene, nylon, compatibilizer CPE-g-MAH (chlorinated polyethylene-graft-maleic anhydride), high-performance composite flame retardant, composite stabilizer, anti-aging agent, thiadiazole vulcanizing agent and aldehyde-amine condensate accelerator. The preparation method comprises the following steps: plasticating, blending on a hot roll compounding mill, sulfurizing and the like. The invention has the advantages of high tearing strength, low hardness, high softness, wide application range, simple formula and simplified technique.