Abstract: Double layer thermal barrier coatings(bond coating is Ni-Cr-Al-Y and ceramic coating is ZrO₂) was prepared by atmospheric plasma sprayed method.Using ABAQUS software,the thermal stress distribution of 3 dimension ellipse interface topography between bond coating and ceramic coating was numerically simulated by indirect coupling method.Relations between thermal stress with location and size of ellipse topography unit were obtained.The calculating results show that the stress is affected by location and size obviously and stress of boundary topography unit is bigger than that of center unit when the size of unit is invariable.The boundary topography units are danger unit and corner points are danger points.The stress of danger point reaches 324 MPa when short half axes is 20.