The invention discloses a smelting device for recovering waste heat. The smelting device comprises a base; an outer cylinder is fixedly mounted at the top of the base; a furnace body is arranged in the outer cylinder; support legs are fixedly connected to the bottom of the furnace body; a transverse plate is fixedly connected to the bottoms of the support legs; two ends of the transverse plate are fixedly connected to two sides of the inner wall of the outer cylinder; and the top of the transverse plate is fixedly connected with a heating pipe. The smelting device is provided with the furnace body, a test tube and a lantern ring; raw metal is accommodated in the furnace body; a fuel is placed on the transverse plate; heat heats the furnace body along with the heating pipe; in the heating process, redundant waste heat is leaded out of the outer cylinder through a guide pipe; through a heat exchange effect of a heat exchanger, the waste heat is leaded in the test tube; water is evaporated through heat of the waste heat; then, the raw metal is fed in the furnace body; and the smelting device uses the waste heat to evaporate the water of the raw metal, so that the utilization rate of the heat is largely increased, and the energy is saved.