The　effects　of　PbO　atmosphere　on　structure　and　electrical　properties　of　Mn-modified　Pb((Zn1/3Nb2/3)(0.20)(Zr0.50Ti0.50)(0.80))O-3　ceramics　were　investigated.　Specimens　were　prepared　with　and　without　a　PbZrO3　protective　ambient,　by　columbite　two-stage　process　in　a　temperature　region　from　1050　to　1200degreesC.　The　results　indicated　that　PbZrO3　powder　is　favored　to　the　liquid-state　sintering　process　of　specimens　in　PbO　vapor　pressure　equilibrium.　The　specimens　sintered　with　PbZrO3　powder　showed　the　homogenous　and　intergranular　microstructure;　whereas,　the　specimens　sintered　without　PbZrO　powder　demonstrated　the　inhomogenous　and　transgranular　microstructure.　Without　protective　PbZrO3　powder,　the　flow　of　PbO　from　the　compact　to　the　exterior　resulted　in　the　formation　of　amorphous　phase　in　grain　boundaries,　which　deteriorated　the　electric　properties　seriously.　By　the　use　of　PbO　protective　atmosphere,　the　excellent　piezoelectric　and　dielectric　properties　(Q(m)　=　1160,　tan　delta　=　0.004,　K-p　=　0.54)　were　obtained　at　1100degreesC　for　2h.　(C)　2004　Elsevier　B.V.　All　rights　reserved.