Abstract: Growth mechanism of thermally growth oxide(TGO) in thermal barrier coatings(TBCs) was investigated by finite element analysis software ABAQUS. After high temperature oxidation for 100 hours, the thickness of TGO increased from 0.5 μm to 6.7 μm. With the increasing of high temperature oxidation, stresses in the peaks, valleys and interface of TGO were obviously larger than in other places. Meanwhile, cracks were prone to initiate and propagate at these locations, and eventually led to spalling of the entire coating. During high temperature oxidization, the total absorbed energy of coating was 43.6 J, some of which was consumed for coating deformation, and the remaining for changes of coating composition and microstructure, and crack propagation.