Nano-structured perovskite-type proton-conducting thin films have been fabricated by SF6 fast atom beam (FAB) etching, with an ordered anodic porous alumina membrane as a lithographic mask. Period hexagonal structures (100 and 500 M) are patterned on laser ablation-deposited SrCeO3 film on MgO (110) substrate. It is found from X-ray diffraction analysis that the lattice constant a, which is perpendicular to the substrate surface, decreases with decreasing periodicity of the nano-structure. The optical transmission and reflection spectra show typical features of surface-relief grating structures.