The invention provides a line fault positioning and warning device comprising a shell, a control circuit unit and a fault indication unit. The fault indication unit consists of a fault indicator lamp, a mechanical warning device and a short message warning module; the mechanical warning device includes a transmitter body; hoodle holes are formed in the laterial peripheral direction of the lower half part of the transmitter body at equal intervals; and hoodles are arranged inside the hoodle holes. When a fault occurs, the transmitter body of the mechanical warning device pops up from the inside of the shell and hoodles at the lower half part of the transmitter body are release; and the hoodle can fall to a place at a distance of two meters from the shell and thus the transmitter body, the hoodle, and a warning rope form a series of strong warning marks that can be discovered easily even at weather with low visibility.