Using X-ray microscope, thermal barrier coatings (TBCs) were imaged with a high resolution of 0.5 μm after high temperature cycles. Three-dimensional segmentation and extraction of thermally grown oxide (TGO) was performed. A finite element analysis model of thermal barrier coatings was established based on real three-dimensional (3D) structure of thermally grown oxide, and the effect of creep and thermal cycles on the stress distribution of thermal barrier coatings were researched. The results of finite element analysis show that the stress decreases greatly due to the influence of creep at the keeping stage. The results of three-dimensional thermal stress distribution shows that the thermal stress at the interface between the bond coat and the TGO is the maximum. The stress of thermal barrier coating increases with the increase of thermal cycle number, but the stress tends to be stable after 15 thermal cycles.