The invention discloses a utilization method for the waste heat of blast furnace slag, belonging to the technical field of utilization of the waste heat of furnace slag. A heat exchange station (6) is built nearby a sedimentation basin (1), and used for installing a spiral slag-flushing water special heat exchanger and a steam-water shell-and-tube head exchanger; the slag-flushing water of a blast furnace enters in a water suction well (3) through a water overflow basin (2), and is conveyed to the heat exchange station (6) from a slag-flushing water supply tube (5) through a slag-flushing pump room (4) at first, heating hot water returns to a slag-flushing main water supply pipeline after heat release, and enters in the slag opening of the blast furnace to perform slag-flushing; and the water-slag mixture enters in a stirring cage machine along a slag groove, enters in the sedimentation basin after being separated, enters in the water suction well (3) through sedimentation, overflow and a slag baffle, so as to form a slag-flushing water circulation system. The utilization method has the advantage that the sensible heat of the blast furnace slag is adequately utilized, thus achieving the purposes of energy conservation and emission reduction.