Abstract: AlSi10Mg Al alloy has the characteristics of high specific strength and high wear resistance, and it has been widely used in aerospace, automobile and ship manufacturing. AlSi10Mg Al alloy was prepared by selective laser melting technology, and the effects of different heat treatment processes on the microstructure and mechanical properties of AlSi10Mg alloy were investigated. The results show that with the increase of heat treatment temperature, the eutectic Si structure is destroyed and the size of Si particles in the alloy increases. The strength and hardness of the alloy show a downward trend, but the plasticity is obviously improved. In addition, the heat treatment changes the fracture mode of the alloy. AlSi10Mg alloy in the as-deposited state is brittle fracture, while it is transformed into ductile fracture after heat treatment.