Sn-doped,　Mg2Si1-x　Sn　(x)　(x　=　0　to　0.6)　bulk　alloys　were　prepared　using　Mg　and　Sn　ingots　as　raw　materials　by　suspended　induction　melting　combined　with　the　spark　plasma　sintering　method,　and　the　effects　of　Sn　doping　on　thermoelectric　transport　properties　were　studied　systematically.　The　results　showed　that　Mg　site　vacancies　caused　by　evaporation　during　the　reaction　process　were　filled　by　excess　Mg　addition　(108　wt.%　of　the　stoichiometric　ratio　of　Mg2Si).　The　resulting　alloy　samples　were　found　to　be　single　phase　and　relatively　dense　(above　98%).　n-Type　semiconducting　characteristic　of　Sn-doped　Mg2Si1-x　Sn　(x)　alloy　was　observed,　and　the　electrical　resistivity　of　all　samples　decreased　with　increasing　temperature.　The　absolute　Seebeck　coefficient　increased　and　the　thermal　conductivity　was　not　changed　significantly　within　the　experimental　Sn　doping　range.　The　dimensionless　figure　of　merit　(ZT)　for　Mg2Si0.4Sn0.6　alloy　reached　its　highest　value　of　0.25　at　400A　degrees　C.