The invention discloses a method for purifying metallic silicon by using aluminum melt, which comprises the following steps: firstly, removing oil from the metallic silicon and washing the metallic silicon to obtain clean metal silicon; secondly, pouring the aluminum melt into the clean metallic silicon to coat a layer of aluminum melt on the surface of the clean metallic silicon, and cooling andsolidifying the layer of aluminum melt; and finally, pouring the product of the cooling and solidification in an atmosphere of an inert gas, preserving the heat, cooling the product to room temperature, soaking the product in mixed solution of hdrochloric acid and hydrofluoric acid for several hours, and completely washing the product by deionized water. In the method, based on a principle that aluminum can absorb impurities in silicon, the primary absorption treatment of the impurities in the metallic silicon is performed to obtain a pure silicon material to be used in a subsequent purification process. The method is a low-cost, low-energy consumption, easy-to-implement physical method for purifying and preparing solar grade silicon. By the method, the purity of the metallic silicon can be improved to 99.99 to 99.999 percent (4 to 5 N) primarily, so the metallic silicon can be used as a silicon material for solar cells or a material to be further purified.