Proton irradiation of Kapton-H films was physically simulated in plasma immersion configuration with hydrogen plasmas. Hydrogen ion was implanted into the samples biased to a negative pulse of 20 kV. Optical transmittance of the sample in the wavelength region of 200-2500nm was determined by a UV-vis-NIR scanning spectrophotometer, and the functional group evolution was examined by X-ray photoelectron spectroscopy (XPS). Atomic force microscopy (AFM) was utilized to determine the roughness and morphology of the samples, and the bulk modification was analyzed by FTIR. The experimental results showed the optical transmittance of the treated sample in the wavelength of 500-2000nm weakened after proton irradiation, and decreased with the increase of irradiation time. Finger-like bulges emerged on the surface of the sample irradiated by ion irradiation for 30 min, and became bigger and denser with the increase of the irradiation time. The content of C element of the sample increased after proton irradiation, while that of N and O elements decreased because of the bonds breakage of C=O, C-O-C and C-N during irradiation process. (C) 2011 Elsevier B.V. All rights reserved.