General drop -out fusion tube top structure, it mainly by cup joint in proper order respectively the operation ring lasso of fusion tube upper end on, moving contact lasso and top pullover, last moving contact lasso on respectively the disjunctor have the wedge contact body and clavate contact physically, operation ring lasso and last moving contact lasso on offered the pinhole respectively, dispose separately on it and to fix the holding pin on fusion tube upper end relevant position with operating ring lasso and last moving contact lasso adjustablely, it has rational in infrastructurely, compact, uses simple to operate, good reliability, can be fit for that various fuse bases are supporting to be used, reduces the deposit of salvageing spare parts, characteristics such as long when reducing power failure and salvageing.