A　novel　surfactant-modulated　precipitation　method　is　proposed　to　produce　pure　perovskite　Pb(Sc1/2Nb1/2)O-3　(PSN)　nanopowders　at　a　low　temperature　of　700　A　degrees　C.　The　samples　were　characterized　by　XRD,　SEM,　TEM,　and　HRTEM,　respectively.　The　results　indicate　that　the　powders　exhibit　a　granular　shape　of　80　nm　in　diameter.　It　is　believed　that　the　nanosize　of　as-prepared　PSN　powders　is　dependent　on　the　well-dispersed　performance,　which　arouse　from　the　combined　effects　of　both　precipitant　TMAH　and　surfactant　CTAB.　The　mechanism　of　the　formation　of　the　pure　perovskite　PSN　nanopowders　is　discussed　in　detail.　Our　method　is　expected　to　create　a　new,　low-cost　route　to　produce　the　promising　nanopowders　of　multi-component　perovskite　systems.