Abstract: When nonvacuum die-casting AlSi10MnMg alloy samples developed by a domestic company were taken as the experimental objects, the effects of heat treatment on the microstructure and mechanical properties of the alloy were investigated. The results showed that the comprehensive performance of nonvacuum die castings decreased after high temperature solution-quenching-artificial aging treatment, and distortion and blistering were prone to occur in the castings. When the die-casting specimens were treated by low-temperature aging only, their yield strength and tensile strength reached 251.8 MPa and 327.1 MPa, respectively, which were 42.6% and 10.5% higher than those of the die-cast specimens, and the elongation after fracture decreased. The main strengthening phases that precipitated in the alloy after low-temperature aging treatments were the Mn₆Si and Mg₂Si phases.