During the coating preparation process, differences in the morphology, size, molten state, flight path, and spreading behavior on the substrate of the feedstock result in a certain degree of undulation within and among the adjacent coating layers. Changes in the geometry of the interface of the coatings make the morphology at the interface more complex, showing irregular and inhomogeneous structural characteristics. It also further makes the stress distribution at the interface uneven, leading to unpredictable failure of the self-healing TBCs at the interface in the subsequent service process, which in turn leads to the warpage or delamination failure of the entire coating. Finite element software was used to simulate the effect of the variation of the surface morphology on the residual stress which is inside the coating and at the interface. By establishing the cosine ideal interface model, it is found that when the wavelength L of interface Ⅰ and interface Ⅱ increases, both the maximum S₂₂ tensile stress and compressive stress of interface Ⅰ and interface Ⅱ decrease. When the amplitude A of interfaces Ⅰ and Ⅱ increases, the stress is affected by both interface roughness and interface buffer stress. Varying the phase offset d between the peaks at the upper and lower interfaces, it is found that the microstructural characteristics of interface Ⅰ have a greater influence on the tensile stress at the peaks of interface Ⅱ . When the valley of interface I faces the peak of interface Ⅱ, this morphology pattern can reduce the maximum tensile stress of interface Ⅱ by 25.7% and avoid excessive stresses at interface Ⅱ. Further, the failure mechanism of the coating is systematically investigated, which provides a more comprehensive theoretical guidance for the optimal control of the interface of the self-healing thermal barrier coatings and the optimal design of the processing technology.