Columnar-structured　thermal　barrier　coating　systems　(TBCs)　possess　a　strain　tolerant　columnar　microstructure　wherein　the　gaps　between　the　columns　are　filled　with　high-porosity　oxides.　A　numerical　model　is　proposed　to　estimate　the　stress　fields　of　the　microcrack　induced　by　calcium-magnesium-alumina-silicate　(CMAS)　infiltration　and　microcrack　propagation　behavior　in　the　yttria　stabilized　zirconia　column　induced　by　dynamic　CMAS　infiltration　is　studied　using　the　extended　finite　element　method.　The　results　demonstrate　that　both　the　stress　and　energy　release　rate　near　microcracks　were　found　to　dramatically　increase　when　CMAS　reached　a　microcrack.　The　present　analysis　reveals　that　the　vertical　cracks　easily　initiate　from　the　microstructure　column　and　coalesce　with　adjacent　horizontal　and　vertical　pores,　thereby　resulting　in　premature　failure　of　TBCs　via　delamination.　©　2020　The　Chinese　Institute　of　Engineers.