Abstract: A series of Mg-6Al-2Sr-xY magnesium alloys were prepared under the protection of argon atmosphere.The effect of Y content on microstructure and mechanical properties of Mg-6Al-2Sr-xY was studied and the existing forms of Y and Sr in the alloy were discussed.The results indicate that the proper addition of Y resulted in the refinement of Mg-6Al-2Sr-xY alloy microstructure.Sr and Y exsited in the forms of Al4Sr,Al2Y and Al3Y phase.Net-like Al4Sr phase was distributed along the grain boundary and particle-like or acicular Al-Y phase was mainly precipitated from the grain.The mechanical properties of the alloys initially ascended and then descended with the increase of Y addition.When Y content was 1.5wt%,compared with Mg-6Al-2Sr alloy,the tensile strength of the alloy was improved by 20.6%,yield strength was increased by 24.6% and the elongation was enhanced by 52.9%.