The invention relates to a cable sheath and a preparation method thereof, belongs to the technical field of cable sheaths, and solves the technical problem that the insulating sheath in the prior artis generally directly attached outside the taped covering by means of co-extrusion and cannot be used alone, especially for a cable requiring partial package or partial repair, which is not applicable. The cable sheath provided by the invention comprises a sheath body and a closing material, wherein the sheath body is composed of a surface layer, a substrate layer, a pressure resistant layer and an insulating layer which are arranged in order from top to bottom; the surface layer is composed of integrally formed convex strips and concave strips, a first occlusion tooth and a second occlusion tooth; and the closing material is a polyurethane adhesive. The cable sheath provided by the invention is not integrally formed with the cable and can be used alone, is especially suitable for cables requiring partial package or partial repair, has the advantages of high strength, good toughness, bending resistance, good flame retardancy, good high temperature resistance performance and the abilityto meet the weathering and corrosion resistance of the cables to provide effective protection against the cables.