Influence of heat treatment on the microstructure and mechanical properties of ZA43 Mn alloy in punch squeeze casting has been studied. The results showed that plasticity of squeez casting ZA43 Mn alloy can be improved by aging treatment （ σ 5 =18%

σ b =430 MPa）

as a result of α and β phases in alloy decomposition

dendritic segregation alleviation

Mn rich phase passivation and disintegration. The casting with high strength （ σ 5 =10%

σ b =510 MPa）can be achieved by solution treatment making Mn rich and Cu rich phases to be decomposed

secondary dispersed phase in matrix to be precipitated and the morphology and distribution of inter dendritic structure to be improved.