The low-temperature ultraviolet (UV) irradiation equipment, developed in our Lab, was used to study the photo-aging of poly (vinyl chloride) (PVC) films at low temperature. The color change kinetics and corresponding structure development of PVC film during low-temperature UV aging were studied through L*a*b* coordinates Commission International d' Eclau-age (CIE 1976 color space) and Ultraviolet spectrophotometer (UV-vis) and Fourier transform infrared spectroscopy (FTIR). It was found that the yellowness difference (Delta b*) and color difference (Delta E*) of the PVC film increased almost linearly with the aging time. Their values had a slower change at lower temperature. The kinetic study showed that the relationship between the velocity of coloration of the PVC film and the temperature agreed well with Arrhenius equation at low temperature. The activation energy of coloration of the PVC film was calculated. The FTIR spectra indicated that photo-dehydrochloration, resulting in the generation of conjugated carbon-carbon double bonds, was the main reaction for PVC during photo-aging at low temperature. Meanwhile, the photo-oxidation was also obvious and could not be neglected. It clearly confirmed that the absorption peaks of conjugated carbon-carbon double bond increased and shifted to longer wavelength during photo-aging in the UV-abs analysis. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci 122: 2588-2593, 2011