In this paper, diamond-like carbon (DLC) films on the inner surface of the polyethylene terephthalate (PET)-bottle were deposited by radio frequency plasma-enhanced chemical vapor deposition (RF-PECVD) with C2H2 as the source of reaction and Ar as the dilution gases.As the humid and gas barrier layer in the inner side of PET battle, the DLC film structure, composition and morphology are analyzed by Fourier transform inferred (FTIR), atomic force microscope (AFM), scanning electron microscope(SEM) and Raman measurement.From the spectrum, it is analysed that the proportion of the acetylene concentration in the mixture gas dominates the film component.The ratio of sp2 and sp3 in the chemical structure is relevant to the plasma power and working pressure.Additionally, the relationship between the discharge conditions and the oxygen transmission rate (OTR) of the PET-bottle are also discussed.