Abstract: In order to analyze the influence of surface effect on the buckling and post-buckling behavior of porous beams under axial pressure, the nonlinear post-buckling governing differential equation of axially extensible beams was established by using Gurtin–Murdoch surface elasticity theory. It was assumed that the pore distribution of the beam has two non-uniform modes, one symmetry and the other asymmetry along its thickness direction. The critical load and post-buckling equilibrium path curve of porous nanobeams under different porosity coefficients were given by the shooting method. The influences of surface material properties on post-buckling behavior were discussed. The results show that nanobeams have very significant surface effects, and the surface effect has an important influence on the buckling and post-buckling behavior of porous nanobeams.