To　explore　new　relaxor-PbTiO3　systems　for　high-power　and　high-temperature　electromechanical　applications,　a　ternary　ferroelectric　ceramic　system　of　Pb(Lu1/2Nb1/2)O-3-Pb(In1/2Nb1/2)O-3-PbTiO3　(PLN-PIN-PT)　have　been　investigated.　The　phase　structure,　dielectric,　piezoelectric,　and　ferroelectric　properties　of　the　as-prepared　PLN-PIN-PT　ceramics　near　the　morphotropic　phase　boundary　(MPB)　were　characterized.　A　high　rhombohedral-tetragonal　phase　transition　temperature　TR-T　of　165　degrees　C　and　a　high　Curie　temperature　T-C　of　345　degrees　C,　together　with　a　good　piezoelectric　coefficient　d(33)　of　420　pC/N,　were　obtained　in　0.38PLN-0.20PIN-0.42PT　ceramics.　Furthermore,　for　(0.8-x)PLN-0.2PIN-xPT　ceramics,　the　temperature-dependent　piezoelectric　coefficients,　coercive　fields　and　electric-field-induced　strains　were　further　studied.　At　175　degrees　C,　their　coercive　fields　were　found　to　be　above　9.5　kV/cm,　which　is　higher　than　that　of　PMN-PT　and　soft　P5H　ceramics　at　room　temperature,　indicating　PLN-PIN-PT　ceramics　to　be　one　of　the　promising　candidates　in　piezoelectric　applications　under　high-driven　fields.　The　results　presented　here　could　benefit　the　development　of　relaxor-PbTiO3　with　enhanced　phase　transition　temperatures　and　coercive　fields.