Relaxor　ferroelectrics　Pb(Sc1/2Nb1/2)O-3　(PSN)　attracted　intensive　attention　due　to　its　unique　properties　such　as　ordering-disordering　transition　of　B/B＇　cations.　In　this　work,　the　effect　of　pH　value　on　the　PSN　powders　by　the　precipitation　method　was　systematically　investigated.　The　experiments　show　that　the　formation　of　perovskite　PSN　was　strongly　related　to　the　pH　condition,　which　impacts　the　chemical　stoichiometry　of　the　precipitates　and　grain　morphologies　of　the　PSN　powders:　at　low　pH　condition,　the　perovskite　PSN　was　accompanied　with　the　pyrochlore　phase　due　to　the　deficiency　of　Pb;　however,　high　pH　value　resulted　in　the　large　size　of　the　powders　due　to　the　strong　agglomeration　effect　of　OH-　wrapping,　even　though　the　pure　perovskite　PSN　powders　was　obtained.　The　PSN　powders　precipitated　at　a　mild　pH　of　8.1　achieved　a　pure　perovskite　PSN　powders　with　chemical　stoichiometry　and　grain　size　of　400　run.　Besides,　the　dielectric　measurements　of　PSN　ceramics　prepared　by　precipitation　method　show　the　typical　relaxor　ferroelectrics　characteristics,　and　a　more　diffusive　phase　transition　than　that　for　PSN　ceramics　fabricated　by　conventional　solid-state　reaction　method.　(C)　2007　Elsevier　B.V.　All　rights　reserved.