Abstract: The in-line wall of the structure of stainless steel sandwich panel is composed of two stainless steel panels and orthogonally arranged stainless steel core tubes. The connection between the core tube and the panel was brazed by copper. In the paper, the stability of the in-line wall of the structure of stainless steel sandwich panel under compression and bending was studied.Firstly, the finite element eigenvalue buckling analysis was carried out, and the formula for calculating the elastic buckling load of the in-line wall and the corresponding regularized aspect ratio λ_n was obtained. The finite element nonlinear analysis was used to study the stress process and failure mechanism. The influence of parameters such as aspect ratio, panel thickness, outer diameter of core tube, wall thickness of core tube and distribution distance of core tubes on the stability bearing capacity of the in-line wall of the structure of stainless steel sandwich panel was obtained, as well as the stability coefficient of axial compression φ_N and pure bending stability coefficient φ_M, and the φ_N -λ_n and φ_M-λ_n curves for stable design were established. Based on the reliable finite element method of in-line wall of stainless steel sandwich panel were designed, and the stability bearing capacity under compression and bending was studied by finite element simulation. The results showed that the design formula could calculate the bearing capacity of the component safely.