The　comparative　studies　of　NiO　and　Pb(Ni1/3Nb2/3)O-3　(PNN)　added　Pb(Zn1/3Nb2/3)O-3-PbZrO3-PbTiO3　(PZN-PZT)　with　the　same　content　level　of　Ni　ions　have　been　performed.　On　the　basis　of　the　XRD　and　TEM　analysis,　it　is　clear　that　NiO　introduction　induces　a　phase　transformation　from　the　morphotropic　phase　boundary　(MPB)　to　the　tetragonal　phase　side,　and　the　corresponding　grain　size　increases　greatly.　In　comparison,　the　system　with　PNN　addition　remains　MPB　structure,　and　the　corresponding　grain　size　increases　slightly.　According　to　the　analysis　of　temperature　dependencies　of　dielectric　constant　and　AC　conductivity,　combined　with　the　observed　evolution　trend　of　ferroelectric　loops,　it　is　reasonable　to　deduce　that　two　types　of　substitution　behaviors　coexist　in　NiO　added　PZN-PZT　system.　The　doping　Ni2+　ions　can　not　only　substitute　for　Ti4+,　Zr4+　and　Nb5+　ions　in　the　inequivalence　replacement,　but　also　substitute　for　Zn2+　ions　in　the　equivalence　replacement.　(C)　2014　Elsevier　Ltd.　All　rights　reserved.