The utility model discloses an insulation sheath applied to an insulation wire end. The insulation sheath is characterized by comprising an insulation sheath body and a lock cap, wherein the insulation sheath body is a hollow cylinder member of which one end is an opening, the lock cap is a hexagonal nut structure, the lock cap is sleeved at a splayed inclination plane opening end of the insulation sheath body to form a protection structure for the insulation wire end in the insulation sheath body, and a fixing structure for the insulation wire end is formed through threads. The insulation sheath can effectively prevent electrical leakage caused by exposure of the insulation wire end, improves operation safety and guarantees electrical network power supply reliability.