The invention relates to a fuse for electrical machinery and an operating method thereof. According to the technical scheme, the fuse is composed of a housing, a metal cover plate, a bolt, a fusing indicator, an indicator melting body, a melting pipe, quartz sands, a working melting body and a knife-shaped contact. The two ends of the housing are connected with the metal cover plate by the bolt. The working melting body is fixed inside the housing and is connected with the indicator melting body; and the fusing pipe is arranged outside the indicator melting body connected with the fusing indicator. The quartz sands are arranged inside the fusing pipe; and the knife-shaped contact is connected outside the working melting body. According to the invention, the fuse has the following beneficial effects: the structure is simple; the fuse can be used and installed conveniently; the operation is simple and forces can be saved; mounting and dismounting become conveniently; the costs are low; the fusing effect is good; the performances are stable; the application rang is wide; and the service life is long.