A　series　of　Sb-doped　Mg-2(Si0.4Sn0.6)Sb-x　(0　＜=　x　＜=　0.025)　solid　solutions　were　prepared　by　an　induction　melting,　Melt　Spinning　(MS)　and　Spark　Plasma　Sintering　(SPS)　method,　namely　the　non-equilibrium　technique　MS-SPS,　using　bulks　of　Magnesium,　Silicon,　Tin,　and　Antimony　as　raw　materials.　The　non-equilibrium　technique　generates　the　unique　multiscale　microstructures　of　samples　containing　micronscale　grains　and　nanoscale　precipitates,　the　multiscale　microstructures　remarkably　make　the　lattice　thermal　conductivities　decreased,　particularly　for　samples　with　the　nanoscale　precipitates　having　the　size　of　10-20　nm.　Meanwhile,　Sb-doping　greatly　increased　the　electrical　performance　of　samples.　Consequently,　the　Sb-doping　combined　with　the　multiscale　microstructures　strategy　remarkably　improves　the　overall　thermoelectric　(TE)　performance　of　Sb　doped　samples,　and　a　high　dimensionless　figure　of　merit　(ZT)　value　of　up　to　1.25　at　723K　is　obtained　with　Mg-2(Si0.4Sn0.6)Sb-0.02　sample　in　a　relatively　wide　temperature　range.