While　thermal　barrier　coatings　(TBCs)　are　being　sprayed　onto　aero-engine　turbine　blades,　or　while　the　engine　blade　is　working,　high　temperatures　and　strong　impact　forces　will　damage　TBCs　under　thermal　cycles,　resulting　in　the　coating　peeling　off　from　the　blades.　The　current　method　of　using　ECT,　IRT,　or　another　method　alone　cannot　achieve　the　real-time　detection　of　coating　defects　with　both　high　precision　and　high　penetration　power.　Two　detection　methods,　namely,　terahertz　pulsed　imaging　(TPI)　and　optical　coherence　tomography　(OCT),　were　combined　to　evaluate　typical　defects　observed　in　TBCs　(including　internal　debonding　cracks,　surface　high-temperature　cracks,　and　surface　etched　cracks).　The　results　showed　that　the　OCT　system　successfully　obtained　the　micron-level　axial　resolution,　but　the　detection　depth　of　the　OCT　system　was　limited.　The　TPI　system　achieved　a　higher　penetration　depth　than　OCT—hence,　it　can　be　used　for　the　nondestructive　detection　and　evaluation　of　the　internal　debonding　defects　in　the　sample—but　its　resolution　needs　to　be　improved.　Following　this　conclusion,　a　method　is　proposed　using　TPI　and　OCT　concurrently　for　the　nondestructive　testing　and　quantitative　evaluation　of　TBCs　on　etched　cracks,　thus　achieving　progress　both　in　terms　of　depth　and　resolution.　In　our　experiment,　defects　with　a　depth　of　519　μm　and　a　width　of　100　μm　were　measured.　The　proposed　method　is　suitable　for　situations　where　multiple　defects　in　TBC　samples　of　blades　need　to　be　detected　simultaneously　during　the　working　process.　When　there　are　defects　deep　inside　the　sample,　more　small　cracks　on　the　surface　can　be　evaluated　to　achieve　a　combination　of　depth　and　accuracy.　©　2024　by　the　authors.