Surface-specific sum-frequency vibrational spectroscopy was used to study the surfaces of polyimide thin films made by spin-coating and ionized cluster beam deposition (ICBD) methods. The surface vibrational spectra in the imide CO region were different between these samples, and the analysis showed the polymer main chains lie mainly along the surface for spin-coated samples, while they are relatively upright in an ICBD film surface. The atomic force microscopy measurement showed that the root-mean-square roughness of these polymer films was similar and not directly related to the surface structure in the molecular level.