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对Al、Si与 Mg元素进行了正交试验设计，采用J Mat-Pro 软件对 Al-Si-Mg 合金进行了成分优化设计与性能研究。结果表明，Si对Al-Si-Mg合金的凝固冷却速度影响最大，其次分别为Fe与Ti，Mg的影响最小。Mg对Al-Si-Mg合金屈服强度、抗拉强度与洛氏硬度的影响最大，依次分别为Fe、Ti和Si。当Al-Si-Mg合金的二次枝晶间距由200μm降至20μm时，抗拉强度由175．2 MPa 增至337．2 MPa。Mg 含量对 SDAS 的影响最大，其次分别为 Si、Fe 与 Ti。Al-6．5 Si-0．7 Mg-0．2Fe-0．2Ti-0．1Zn-0．1Mn-0．1Cu合金经3级固溶2级时效热处理后的平均抗拉强度、屈服强度与伸长率分别为371 MPa、310 MPa与5．84％，与JMat-Pro软件计算结果较为接近。铸态组织下Si 相呈现为板片状或针状，热处理后Si 相逐渐球化，热处理态合金断裂以韧窝断裂为主。“,”The components optimized design and performance analysis of Al-Si-Mg based alloy were inves-tigated systematically by the orthogonal experimental design of the four factors to three levels,combined with the JMat-Pro material simulation software.The results show that the Si element has the strongest role for the cooling rate of Al-Si-Mg based alloy during the solidification process,followed by the Fe ele-ment and Ti element,whereas the Mg element exhibits the minimal impact.Mg has the most obvious effect on the yield strength,tensile strength and hardness (HRC)of Al-Si-Mg based alloy,followed by Fe element and Ti element,Si element.The tensile strength of the alloy is increased to 337.2 MPa from 175.2 MPa with the SDAS of the Al-Si-Mg based alloy decreased from 200μm to 20μm,where the Mg element is dominant role in the SDAS,followed by the Si element,Fe element and Ti element.After three step solid solution and the two step aging heat treatment,the average tensile strength,yield strength and elongation of Al-6.5Si-0.7Mg-0.2Fe-0.2Ti-0.1Zn-0.1Mn-0.1Cu alloy reach 371 MPa,310 MPa and 5 .84% ,respectively,which is near to the calculation of JMat-Pro software.The structure of Si phase in the alloy at as-cast state exhibits plate-like or needle,while the morphology is converted into spheroidization ones gradually after heat treatment,and the fracture morphology is characterized by the dimple fracture.