The　piezoelectric　energy　harvester　(PEH)　for　self-powered　high-temperature　microsensors　puts　forward　an　urgent　need　for　high-temperature　fine-grained　piezoceramics　with　a　high　piezoelectric　charge　coefficient　(d(33)),　which　is　still　a　huge　challenge　for　material　design.　This　study　proposes　a　design　strategy　for　building　an　intergranular　particle　bridge　(IPB)　structure,　which　solves　the　bottleneck　in　high-temperature　piezoceramics,　that　is,　difficulty　in　obtaining　both　a　dense　and　fine-grained　structure　together　with　high　d(33).　The　IPB　has　a　dual　function,　that　is,　inhibiting　the　migration　of　the　grain　boundary　during　the　densification　process　to　achieve　a　fine-grained　structure　and　assisting　in　the　construction　of　hierarchical　nanodomain　patterns　to　increase　the　d(33).　Using　partially　amorphous　nanopowders　as　the　precursors,　the　0.345BiScO(3)-0.615PbTiO(3)-0.04Pb(In1/2Nb1/2)O-3　piezoceramics　with　an　IPB　structure　prepared　by　pressureless　sintering　technology　have　an　average　grain　size　of　only　0.26　mu　m　and　the　d(33)　is　as　high　as　343　pC/N,　which　is　significantly　better　than　the　previous　works.　More　importantly,　the　PEH　made　of　optimized　materials　has　an　excellent　power　generation　capacity　at　a　high　temperature　of　250　degrees　C,　showing　important　application　prospects　in　driving　high-temperature　microsensors.　The　design　strategy　proposed　in　this　work　can　provide　a　reference　for　the　preparation　of　more　high-performance　fine-grained　piezoceramics.