Post-heat treatment is the most common post-processing method for relieving large residual stress in metallic products produced by selective laser melting (SLM). Moreover, since the mechanical properties that are deemed superior for desirable can be often obtained after heat treatments in materials by controlling the secondary phases or precipitates, it is necessary to investigate the structural transitions and property changes of the SLM-processed material after the annealing process to provide theoretical support for obtaining the desired performance. In this study, the effect of post-heat treatment on microstructural evolution and property change in the SLM-processed Al-10Si based alloy was investigated. The post heat treatments were performed at different temperature in the range from 270 ℃ to 320 ℃. From the results of the tensile test, as the heat-treatment temperature increases from 290 ℃ to 300 ℃, the strengths s in the as-built state were discontinuously separated and semi-homogenized especially when heat-treated above 300 ℃. It contributes to significant increase of total elongation of the alloy by delaying the melt pool boundary decohesion during tensile deformation. Consequently, the combinatidecrease while the elongation increases by 2.2 %. Microstructures and tensile properties of two heat-treated samples at 290 ℃ and 300 ℃, respectively, were representatively characterized and then compared to those of as-built one. Interestingly, Si phases that networkon of strength-ductility could be successfully enhanced in the annealed samples as compared with those in the as-built samples. In this regard, the post-heat treatment can be a strategy to ensure the reliability of product quality and improve the mechanical properties of SLM-processed Al-10Si based alloys. Moreover, this work will facilitate the beneficial tailoring of the heterogeneous microstructure for desirable performance used in edge applications by offering the theoretical guidelines to optimize the heat treatment condition of SLM-processed materials.