Pulse ion beam treatment was employed for polyethylene (PE) surface ;modification. Ultraviolet, infrared (IR), IR-attenuated total reflection spectroscopy (IR-ATR), and X-ray photoelectron spectroscopy methods, as well as wetting angle measurement, were used for the analysis of PE structural changes. Theoretical calculations and experimental data showed treated PE surfaces to have a layered structure. It was found that the upper layer contains various products of PE oxidation and the lower layer contains products of PE decomposition, that is, condensed aromatic structures.