Effect of substrate conditions, including material type, thickness and radius of substrate, on residual thermal stresses of plasma spraying Sm2Zr2O7/YSZ TBCs was analyzed through finite element method in this paper. The radial and shear stresses of the coating decrease with increasing of distance from the center to edge, and they decrease abruptly at the edge of the specimen, while the axial residal stress increase abruptly at the edge of substrate. All residual stresses increase with increasing of thermal expansion coefficient of substrate. The thickness of substrate has slight effect on the radial residual stress, axial residual stress and shear stress are almost uneffected by substrate thickness. The optimum thickness of substrate is 10mm. Radius of substrate have no effect on radial stress when it is greater than 28mm.