The　question　as　to　which　piezoelectric　composition　is　favorable　for　energy　harvesting　has　been　addressed　in　the　past　few　years.　However,　discussion　on　this　topic　continues.　In　this　work,　an　answer　is　provided　through　a　feasible　method　which　can　be　used　in　selecting　piezoelectric　material.　The　energy　harvesting　behavior　of　hard　(P4　and　P8)　and　soft　(P5　and　P5H)　lead　zirconate　titanate　(PZT)　ceramics　was　investigated.　The　results　show　that　the　maximum　piezoelectric　voltage　coefficient　g(33)　and　transduction　coefficient　d(33)　x　g(33)　were　obtained　in　P5　ceramic.　Meanwhile,　the　power　generation　characteristics　at　low　frequencies　were　compared　by　the　vibration　energy　harvester　with　a　cantilever　beam　structure.　The　results　indicate　that　the　energy　harvester　fabricated　by　the　P5　ceramic　with　the　maximum　d(33)　x　g(33)　values　also　demonstrated　the　best　power　generation　characteristics.　The　results　unambiguously　demonstrate　that　the　power　density　and　energy　conversion　efficiency　of　the　energy　harvesting　devices　are　dominated　by　the　d(33)　x　g(33)　value　of　the　piezoelectric　materials.