The utility model provides a prefabricated appurtenance of welding steel pipe sleeve pipe belongs to electrical construction technical field. Its technical scheme does: a prefabricated appurtenance of welding steel pipe, includes the support, the support is put up and is located by the trusteeship the landing leg of trusteeship frame both sides constitutes, be provided with the through -hole on the trusteeship frame, trusteeship frame below is provided with the base, the middle part of base is provided with the bracing piece, trusteeship frame with be provided with the casing seat between the base, the lower part of casing seat is provided with the stay tube, the stay tube with the bracing piece cup joints, the fixed sleeve pipe that is provided with on the casing seat, sheathed tube upper end by the through -hole passes the trusteeship frame. The beneficial effects of the utility model are that: this simple structure, convenient to use can reduce the construction potential safety hazard, guarantees that electric pipe inserted casing length is unified, guarantees the electricity and manages the straightness that hangs down, improves welding?quality, improves the efficiency of construction.