Abstract: It first compared and analyzed the microstructure and properties of tractor engine aluminum alloy by different heat treatment processes. The results showed that the properties of aluminum alloy have been greatly improved after heat treatment. If the material properties are given priority, the single-stage heat treatment aging of 180 ℃× 4 h should be used. If the process efficiency and cost are given priority, the two stage heat treatment aging of 150 ℃×1 h+170 ℃×1 h can be used.