Selective laser melting (SLM) is a metal additive manufacturing technology based on powder bed melting that enables rapid melting and solidification by scanning the metal powder layer by layer with a high-energy laser beam and finally forms dense metal parts with complex geometric structures. This technology offers significant advantages in

aerospace, biomedical and automotive manufacturing because of its high degree of digital design freedom, excellent material utilization and near-net formation. As representative lightweight structural materials, Al-Si alloys have become a research hotspot in the field of metal additive manufacturing because of their low density, high specific strength and wide solidification interval adapted for the SLM process. However, the mechanical properties of SLM-formed Al-Si alloys still have significant defects: their plasticity is insufficient (approximately 7% in the horizontal direction and approximately 4% in the vertical direction), and they have severe anisotropy, which makes it difficult to meet the requirements of high reliability of load-bearing components in the aerospace field. In this paper, the dynamic changes in the furnace hearth of Al-Si alloys with different SLM systems are analysed, the microstructure characteristics, mechanical properties and effects of heat treatment on the mechanical properties of selective laser melted Al-Si alloys are reviewed, and future composition modifications of Al-Si alloys are proposed.