The different effects of surface acoustic waves (SAWS) on low and high index Cu surfaces were revealed by photoelectron emission microscopy (PEEM). The atomic scale surface structures of thin polycrystalline Cu films prepared by annealing and sputtering were inferred by the characteristic CO stretch frequency in the infrared reflection absorption spectra. The SAW propagation decreased the PEEM intensity for the low index planes, such as Cu(111), whereas it increased the PEEM intensity for the high index planes and step sites formed by sputtering. The results indicated that the SAWS enhanced the work function of a densely packed Cu surface and reduced that of a less packed Cu surface with coordinatively unsaturated metal atoms. Dynamic and vertical lattice displacement by SAWS was proven to have prominent effects large enough to change the electronic structures of metal surfaces.