Abstract: A lamp string with an open-circuit-proof structure, which comprises a socket, a bulb receptacle, a bulb and a fuse assembly; the center hole of the socket is furnished with a rectangular cavity for receiving a fuse assembly, and an outer rectangular cavity for mounting bulb receptacle plugged with a bulb; the center of the socket is furnished with a fuse assembly; in case of the tungsten filament of a bulb being burned out, or a bulb receptacle of a socket being lost, the power-supply circuit can still be maintained in a closed circuit condition through the fuse assembly, i.e., the whole lamp string can be always in lighting-up condition.