The graphite oxide (GO) was reduced successfully by electron-beam irradiation without solution chemistry and high temperature, where the chemical structural changes and gaseous species released during the exposure was monitored directly by X-ray photoelectron spectroscopy/mass spectrometer. The degree of reduction of GO can be tuned effectively by way of electron beam intensity and irradiation time, resulting a high C/O ratio of 5.27. The evolution of C 1s spectra with irradiation time was also investigated. The CO, CO2, H-2 molecules and several organic species were detected during the irradiation, confirmed that the electron beam induced the photoreduction of GO. The combined chemical structure evolution and gas species analysis make the XPS-MS highly desirable as a powerful in situ analytical instrument for tracking the reaction process. The electron-beam-induced reduction described in detail here provides potential way to fabricate graphene device from GO in one step. (C) 2017 Elsevier B.V. All rights reserved.