It　is　known　that　residual　stress　is　the　main　factor　causing　the　final　failure　of　thermal　barrier　coatings　(TBCs).　However,　it　is　still　unclear　how　the　stress　governs　the　cracking　sequence.　In　this　paper,　atmospheric　plasma-sprayed　(APS)　8　wt%　yttria-stabilized　zirconia　(YSZ)　TBCs　were　subjected　to　isothermal　heat　treatment　at　1050　degrees　C　for　different　time.　The　cracking　evolution　and　the　underlying　mechanical　mechanisms　for　cracking　were　investigated.　Residual　stress　distribution　through　the　YSZ　thickness　was　evaluated　using　Raman　spectroscopy.　It　is　found　that,　after　thermal　exposure,　the　in-plane　residual　compression　in　the　top-coat　(TC)　near　the　TC/thermally　grown　oxide　(TGO)　interface　increases　as　the　TGO　thickens,　inducing　tensile　stresses　normal　to　the　interface　in　the　TC　close　to　the　undulation　crests.　A　spherical　analytical　model　is　used　to　evaluate　this　tensile　stress,　and　the　result　shows　that　it　rises　with　the　TGO　growth.　This　normal　tensile　stress　is　the　driving　force　for　cracking　of　TBCs.　Cracking　parallel　to　the　TGO/TC　interface　first　initiates　in　the　TC　near　the　interface,　and　then　coalesces　with　the　cracks　within　the　TGO　and　at　the　bond-coat　(BC)/TGO　interface,　leading　to　the　final　delamination.　Because　TC　has　a　relatively　low　fracture　toughness,　the　delamination　trajectory　is　primarily　in　the　TC　near　the　TGO/TC　interface　and　along　the　pathway　that　contains　inter-splat　cracks,　pores　and　weak　splat　boundaries.　The　results　indicate　that　the　large　in-plane　compressions　play　a　significant　role　in　the　cracking　evolution　of　TBCs　because　they　induce　normal　tensile　stress　in　the　TC　or　at　the　TGO/BC　interface.　A　cracking　pattern　dominated　by　the　stress　evolution　is　established　in　this　work　and　it　will　provide　an　informed　basis　for　improving　the　durability　of　APS-TBCs.