The invention discloses a metallic silicon refining deep impurity-removing method, and solves a problem that impurities are not adequately diffused in a refining process of current metallic silicon sothat the impurities are not completely removed. The method comprises the following steps: placing the metallic silicon in a quartz crucible, and using a vacuum smelting furnace to heat and vacuumize;injecting protective gas; while a smelting temperature is risen to 1450-1750 DEG C, feeding chlorine to the bottom of the quartz crucible, and heat-preserving for 1-4 hours; descending the quartz crucible, and enabling high-purity silicon melted liquid in the quartz crucible to be gradually and directionally solidified and purified from bottom to top, to obtain a high-purity silicon ingot; aftercooling the quartz crucible, taking out the quartz crucible, and cutting the top of the high-purity silicon ingot and a part adhered to the quartz crucible, wherein the quartz crucible comprises a crucible body and concave and convex parts installed on the inner side wall of the crucible body. The method has the advantages of adequate diffusion and removal of the impurities in the metallic silicon, good purification effect and the like.