<p>Although extensive studies have been conducted on the buckling behavior of nanoscale beams, the coupled influence of surface/interface effects in multilayered piezoelectric graded porous structures has not been fully addressed. To better investigate the influence of surface/interface effects on the buckling and post-buckling behavior of nanoscale beams, a multilayered piezoelectric graded porous nanobeam considering both surface and interface effects was established. The structural model is composed of a bulk layer, two interface layers, two piezoelectric layers, and two surface layers for a total of seven layers, in which the piezoelectric layers are close to the surface of the main body layer and carries the electric potential of the whole structure. Combining the Gurtin–Murdoch surface elasticity theory with the geometrical nonlinear beam theory, the post-buckling control differential equations about the nanobeams are established by linking some variables affecting the surface/interface effects. Afterwards, the post-buckling behavior of multilayer structured nanobeams about electromechanical coupling is investigated by shooting method of solution. Key parameters including surface effects, interface effects, small-scale effects, and piezoelectric effects on the nonlinear post-buckling of piezoelectric are nanobeams quantitatively analyzed.</p>