Abstract: Outgassing of polymer materials induced by vacuum ultraviolet (VUV) may cause molecular contamination. In this paper, the polyimide (PI) film is radiated with the VUV irradiation by using the VUV experimental facility, and the mass loss for the PI sample is determined by utilizing the outgassing contamination condensation effect facility. The topographical analysis and the chemical structure are studied by the SEM and the XPS, respectively. Results show that the mass loss for the polyimide induced by VUV irradiations improves and saturates with the increase of the irradiation time. The surface topography of the PI sample doesn't change significantly. The XPS analysis indicates that the content of the C–O enhances, whereas that of the C=O is reduced.