The　reliability　of　piezoelectricity　under　thermal-cycling　is　an　important　consideration　for　the　practical　application　of　Pb-free　piezoelectric　materials.　In　this　paper,　we　investigated　the　effect　of　thermal-cycling　on　the　piezoelectricity　of　0.5Ba(Zr0.2Ti0.8)O3-0.5(Ba0.7Ca0.3)TiO3　(BZT-BCT)　Pb-free　piezoceramic.　The　results　show　that,　in　BZT-BCT,　the　tetragonal-orthorhombic　(T-O)　transition　causes　a　strong　piezoelectricity　degradation　(∼40%　reduction　after　60　thermal　cycles　between　−40　°C　and　50　°C),　whereas　the　orthorhombic-rhombohedral　(O-R)　transition　only　leads　to　negligible　degradation　during　the　thermal-cycling　test,　indicating　a　weak　depoling　effect.　The　comparative　studies　made　between　BZT-BCT　and　BaTiO3　(BT)　reveal　that　the　weak　depoling　effect　results　from　the　diffuseness　of　the　O-R　transition　in　BZT-BCT　and　weak　domain　pattern　change　across　the　transition.　Our　work　implies　that　Pb-free　piezoelectrics　with　good　thermal-cycling　stability　can　be　achieved　through　engineering　the　normal　ferroelectric-to-ferroelectric　transition　to　a　diffused　one,　which　may　help　to　design　new　Pb-free　piezoelectric　materials　with　good　thermal-cycling　stability.　©　2020　Elsevier　B.V.