The invention discloses a blast furnace water slag iron removal device. The device comprises a slag melting ditch, a slag flushing water pipe, a water slag ditch, a slag collecting tank, a belt conveyor, a separating device, an iron collecting tank, a water slag conveying device, a water collecting tank and a circulating water pump, wherein the slag collecting tank is used for receiving the waterslag and the slag flushing water which is discharged from the water slag ditch, moreover, on one hand, the slag flushing water is filtered and discharged into the water collecting tank, and on the other hand, the water slag is transferred to the belt conveyor; the separating device is arranged at the tail end of a belt of the belt conveyor, the separating device is provided with magnetism, iron particles mingled in the water slag are separated from the water slag and fall into the iron collecting tank, and other impurities are transferred to the water slag conveying device; the water in the water collecting tank is pumped to the circulating water pump, so that the water is recycled; and the separating device separates the slag iron in the water slag at the tail end of the belt, so that effective recovery of the iron particles mingled in the water slag is realized. The blast furnace water slag iron removal device is additionally arranged on the basis of the existing process and invention, and the cost can be saved.