Abstract: In order to fully exert the potential of high-strength aluminum alloy materials, four different heat treatment systems were selected from the perspective of thermal strengthening, and the heat-treated aluminum alloy SLM forming samples were studied from the aspects of phase, microstructure, and performance. Finally, the most suitable heat treatment process was screened out. The results show that, the sample with the enhanced aging(EA) heat treatment of 300℃/6 h/furnace cooling has the highest tensile strength of 575 MPa, which is 25% higher than that of the original SLM forming sample without heat treatment. The elongation decreases to some extent, but still meets normal requirements. The strengthening mechanisms are mainly the following three: solid solution strengthening brought by supersaturated Mn element solid solution,fine and thermally stable microstructure morphology leading to fine grain strengthening, and second-phase strengthening brought by nano-scale Al₃Sc phase precipitates generated after heat treatment.