Abstract: Provided is a method for preparing high-purity aluminum by directional solidification, comprising the steps of: providing 4N to 5N aluminum as raw material, heating the same to a temperature of 670° C. to 730° C., maintaining the temperature for 7 minutes to 80 minutes, cooling the bottom of chamber (3) to allow the aluminum liquid crystallizing in a direction from the bottom to top of the chamber (3) for 1 hour to 8 hours to obtain a crystalline ingot, during the crystallization process of a finished product of crystalline ingot, stifling and heating the aluminum liquid, maintaining a particular temperature gradient of the aluminum liquid, and removing a portion of the crystalline ingot from one end of the ingot, the remaining portion being the high-purity aluminum. Also provided is a smelting furnace, comprising a shell (1), a heating device (2), a chamber (3), a temperature measurement device, a stirring device and a cooling device (6).