Thermal　depolarization　is　an　insurmountable　obstacle　to　the　application　of　piezoceramics　and　there　is　still　controversy　about　its　physical　origin.　In　this　work,　taking　four　representative　piezoceramics　(0.94　(Na0.5Bi0.5)TiO3-0.06BaTiO(3),　0.2Pb(Zn1/3Nb2/3)O-3-0.8Pb(Zr0.5Ti0.5)O-3,　0.36BiScO(3)-0.64PbTiO(3)　and　Ba0.85Ca0.15Ti0.9Zr0.1O3)　as　an　example,　by　using　a　designed　in-situ　Berlincourt-type　high-temperature　d　33　meter,　combined　with　variable　temperature　X-ray　diffraction　and　dielectric　temperature　spectrum　test,　it　was　confirmed　the　depolarization　behavior　is　directly　related　to　the　structural　phase　transition,　meanwhile　it　is　reasonable　to　apply　the　peak　value　of　piezoelectric　coefficient　with　temperature,　T-dp,　as　the　depolarization　characteristic　temperature.　More　importantly,　the　original　in-situ　varied　temperature　d(33)　meter　design　helps　to　investigate　the　temperature　dependent　piezoelectric　mechanism　of　various　piezoceramics.　(C)　2018　Elsevier　B.V.　All　rights　reserved.