Abstract: A high-strength and high-toughness non-heat-treatable die-casting aluminum-silicon alloy and a preparation method therefor are provided. The alloy includes the following components in percentage by weight: 8.0-10.0% of Si, 0.1-0.5% of Mg, 0.5-0.8% of Mn, 0.05-0.5% of Cu, 0.05-0.2% of Ti, 0.01-0.05% of Sr, 0.01-0.1% of V, 0.01-0.15% of RE, less than 0.2% of Fe, less than or equal to 0.4% of other impurities and the balance of Al. Based on modification refinement of eutectic Si by Sr, during preparation, the elements V and RE are imported to further significantly refine eutectic Si structures, so that the alloy obtains features of high strength and high toughness with a high Si content. Under a die-casting condition, the yield strength of the alloy can be 120-160 Mpa, the tensile strength thereof can be 260-320 Mpa and the ductility thereof can be 10-15%.