Vibration　energy　harvesters　(VEHs)　can　transform　ambient　vibration　energy　to　electricity　and　have　been　widely　investigated　as　promising　self-powered　devices　for　wireless　sensor　networks,　wearable　sensors,　and　applications　of　a　micro-electro-mechanical　system　(MEMS).　However,　the　ambient　vibration　is　always　too　weak　to　hinder　the　high　energy　conversion　efficiency.　In　this　paper,　the　integrated　frame　composed　of　piezoelectric　beams　and　mechanical　amplifiers　is　proposed　to　improve　the　energy　conversion　efficiency　of　a　VEH.　First,　the　initial　structures　of　a　piezoelectric　frame　(PF)　and　an　amplification　frame　(AF)　are　designed.　The　dynamic　model　is　then　established　to　analyze　the　influence　of　key　structural　parameters　on　the　mechanical　amplification　factor.　Finite　element　simulation　is　conducted　to　study　the　energy　harvesting　performance,　where　the　stiffness　characteristics　and　power　output　in　the　cases　of　series　and　parallel　load　resistance　are　discussed　in　detail.　Furthermore,　piezoelectric　beams　with　variable　cross-sections　are　introduced　to　optimize　and　improve　the　energy　harvesting　efficiency.　Advantages　of　the　PF　with　the　AF　are　illustrated　by　comparison　with　conventional　piezoelectric　cantilever　beams.　The　results　show　that　the　proposed　integrated　VEH　has　a　good　mechanical　amplification　capability　and　is　more　suitable　for　low-frequency　vibration　conditions.