In this paper, the surface properties of polyacrylonitrile-based carbon fibers is improved by electron-beam (EB) irradiation in maleic anhydride/acetone solution at 100, 150, 200 and 150 KGy. Experimental study of this paper is carried out to identify surface topography, surface chemical composition and functional groups, adsorption ability and interface properties of CF/epoxy composites. The results reveal that the roughness of carbon fiber surface is increased obviously after modification by EB irradiation grafting technology. The ratio value of O/C and the relative content of oxygen functional groups on fiber surface are improved effectively, comparing with the unmodified carbon fiber. Besides, adsorption of carbon fiber on epoxy and the mechanical performance of CF/epoxy composites are clearly enhanced after irradiation grafting modification. Copyright © 2012 John Wiley & Sons, Ltd.