The invention relates to a system and technology for realizing low-temperature multi-effect seawater desalination (LT-MED) production through residual heat of blast-furnace cinder flushing water. The system comprises a cinder flushing water heat extraction system, and a low-temperature multi-effect seawater desalination water production system; the cinder flushing water heat extraction system consists of a cinder flushing tank, a heat exchanger, an insulating water tank, a water collecting tank, a first desalination water pump and a hot water pump; and the low-temperature multi-effect seawater desalination water production system consists of a flash evaporator, a supercharger, a residual heat boiler and a low-temperature multi-effect seawater desalination device. The system can convert low-temperature residual heat resources into low-quality steam, and combines the low-quality steam with LT-MED, and the water production cost of the low-temperature multi-effect seawater desalination can be greatly lowered.