The invention relates to an early warning device for boosting of municipal administration water supply pipes in a long and large underwater traffic tunnel, and relates to the technical field of underwater traffic tunnels. The early warning device comprises an early warning control center, a municipal administration water supply pipe monitoring system and a waste water drainage information monitoring system; a displayer is connected with an early warning control center host which is connected with the early warning device and a printer through cables, the municipal administration water supply pipe at a tunnel inlet and the municipal administration water supply pipe at a tunnel outlet are provided with a manual-electric integrated butterfly valve and an electromagnetic flowmeter correspondingly, the manual-electric integrated butterfly valve is connected with the early warning control center host through a cable, and the electromagnetic flowmeter is connected with the early warning control center host through a cable. By means of the early warning device, the pipe leakage phenomena can be found in time and can be repaired in real time, in-advanced early warning is achieved, boosting of the municipal administration water supply pipes is prevented, and the amount of accident waste water in the tunnel is effectively controlled.