The invention relates to the field of nonferrous metal preparation, in particular to a self-metamorphic treatment method for an eutectic aluminum-silicon alloy. According to the self-metamorphic treatment method for the eutectic aluminum-silicon alloy, the eutectic aluminum-silicon alloy after spheroidizing annealing treatment is taken as a metamorphic agent to perform self-metamorphic treatment on an eutectic aluminum-silicon alloy body; and the spheroidized and annealed eutectic aluminum-silicon alloy with the weight percentage being 0.1-1.0% is adopted, after the metamorphic treatment is performed on the eutectic aluminum-silicon alloy within the temperature range of 630-750 DEG C, the microscopic tissue of the eutectic aluminum-silicon alloy is obviously improved, and the mechanical property of the eutectic aluminum-silicon alloy is significantly improved.