Piezoelectric　energy　harvester　converts　low-frequency　vibrational　energy　in　the　environment　into　electrical　energy,　enabling　the　purpose　of　self-supplying　power　for　low-energy　consumption　devices.　The　key　to　miniaturizing　energy　harvester　is　the　buildup　of　the　submicron-grained　ceramic　with　a　high　transduction　coefficient　(dxg),　which　is　still　a　big　challenge　from　a　technical　point　of　view.　In　this　work,　the　popular　ternary　system　of　Pb(Zn1/3Nb2/3)O-3-Pb(Zr0.5Ti0.5)O-3　(PZN-PZT)　has　been　selected　as　objective　compound,　and　the　submicron-grained　ceramics　were　prepared　by　a　combination　of　high-energy　ball　milling　and　pressureless　sintering　technology.　The　results　revealed　that　nanocrystalline　PZN-PZT　powders　can　be　synthesized　by　one　step　mechanochemical　route　without　the　calcination　stage.　Using　these　nanopowders　as　precursors,　dense　ceramics　with　different　grain　size　have　been　prepared　through　tailoring　the　sintering　temperature.　The　study　of　size-dependent　energy　harvesting　characteristic　evidenced　an　optimum　transduction　coefficient　of　7980x10(-15)　m(2)/N　was　obtained　for　950　degrees　C　sintered　specimen,　which　has　uniform　microstructure　with　mean　grain　size　of　0.33　mu　m.　In　the　mode　of　the　cantilever-type　energy　harvester　constructed　by　this　material,　the　output　power　at　low　frequency　of　89　Hz　was　as　high　as　69　mu　W　at　an　acceleration　of　10　m/s(2),　showing　the　suitability　for　piezoelectric　generators　harvesting　environmental　vibrational　energy.