For　low-temperature　firing　of　Pb0.94Sr0.06(Ni1/2W1/2)(0.02)(Mn1/3Nb2/3)(0.07)(Zr0.51Ti0.49)(0.91)O-3　(PNW-PMN-PZT)　system,　BiFeO3　is　selected　as　the　sintering　agent.　In　this　study,　the　effects　of　BiFeO3　addition　and　sintering　temperature　on　the　microstructures　and　piezoelectric　properties　of　the　ceramics　were　investigated　in　detail.　The　ceramic　with　10　mol%　BiFeO3　sintered　at　950　degrees　C　possesses　optimal　microstructure　and　piezoelectric　properties.　However,　with　the　increase　of　sintering　temperature　the　lower　relative　density,　abnormal　grain　growth,　and　secondary　phase　accumulated　at　grain　boundaries　are　observed,　which　deteriorates　the　piezoelectric　properties.　For　the　ceramics　with　different　BiFeO3　addition　sintered　at　950　degrees　C,　the　densification　process　and　the　grain　growth　are　improved　by　suitable　BiFeO3,　while　the　morphotropic　phase　boundary　(MPB)　moving　to　the　Ti-rich　direction　and　the　shrinkage　of　crystal　cell　occur.　However,　extra　BiFeO3　inhabits　the　grain　growth　and　introduces　more　cavities　into　the　materials.　Because　of　the　microstructural　changes　that　accompany　the　addition　of　BiFeO3　and　the　resulting　decrease　in　sintering　temperature,　the　maximum　values　of　the　piezoelectric　properties　are　attained.　By　doping　with　10　mol%　BiFeO3　the　sintering　temperature　of　the　PNW-PMN-PZT　system　can　be　lowered　successfully　from　1200　to　950　degrees　C,　while　the　excellent　electric　properties　are　kept.