The　non-isothermal　heating　process　of　Mg-Sn　powder　mixture　was　studied　by　differential　scanning　calorimetry(DSC)　technique　and　the　synthesis　kinetics　Of　Mg2Sn　was　evaluated　by　the　model-free　and　model-fitting　methods.　The　activation　energy　and　conversion　function　of　Mg2Sn　synthesis　reaction　are　calculated　to　be　281.7　kJ/mol　and　g(alpha)=[-ln(1-alpha)](1/4),　respectively.　The　reaction　mechanism　of　2Mg+Sn　-＞　Mg2Sn　under　non-isothermal　condition　is　regarded　as　＂nucleation　and　growth＂.　During　the　non-isothermal　heating　process,　the　phase　transformation　occurred　in　the　Mg-Sn　powder　mixture　was　analyzed　by　XRD　and　the　microstructure　evolution　of　Mg2Sn　was　observed　by　optical　microscopy,　which　is　in　good　agreement　with　the　reaction　mechanism　of　2Mg+Sn　-＞　Mg2Sn　deduced　from　the　kinetic　evaluation.