To provide a method and system for discharging flue dust for a blast furnace, preventing high-temperature flue gas and the large amount of steam from leaking into the atmosphere when discharging the flue dust generated in the blast furnace and reducing cost required for recycling of the flue dust by pelletization.

This dust discharging system for the blast furnace includes: a dust collector 90 collecting the flue dust 907 from the flue gas generated in the blast furnace; a first discharge pipe 903 connected to the duct collector 90; a separator 2 connected to the first discharge pipe 903 and separating the residual flue gas in the flue dust 907; and an airtight tank 3 arranged below the first discharge pipe 903 and receiving the dried flue dust 907 separated from the residual flue gas. Further, the dust discharging system is provided with a screw conveyor 1 connected between the first discharge pipe 903 and the separator 2 and conveying the flue dust 907 in the first discharge pipe 903 in the direction of the airtight tank 3.