Reusable protective tube

The utility model discloses a reusable protective tube, comprising an upper cover and a lower cover, metal caps wrapped on two ends of the upper cover and the lower cover, a first contact plate disposed on the lower cover, a movable contact spring whose fixed end is fixedly connected with the bottom surface of the first contact plate, a metal sheet which contact movable contacts on the bottom surface of the movable end of the movable contact spring, a heating coil fixedly connected with the metal sheet, and a second contact plate which is fixedly connected with the heating coil. The movable contact spring is provided with at least a salient point on the bottom surface between the fixed end and the movable end. The lower cover is also provided with a temperature strip. The salient points are disposed on the temperature strip. The protective tube can be repeated used, and does not need changing after the protective tube plays a role, thereby greatly improving usage convenience and reducing use cost.