Abstract: As an innovative curing technology conforming to the developing trend of low cost and nuisance free, the electron beam (EB) curing of composites has been receiving extensive attention in recent years. Many works about fundamental research of EB curing should be done to promote its development. The effects of reinforce fiber on electron beam curing process and curing degree of epoxy resin matrix were studied in the paper. The results of observing the cured areas indicate that the obvious interspace exists around the fiber in the cured mixture of untreated carbon fiber and epoxy resins. After the carbon fiber was treated with acid, the combination at interface of fiber and resin matrix is improved in the radiated samples. The curing degree in the cured samples containing fiber decreases with the radiation depth, unlike the top curing degree that occurs at some depth instead of the radiated surface in the neat resin system. When the reinforce fibers are mixed with resin, the thickness of the radiation-cured area and curing degree decrease. The effect of carbon fiber is more obvious than that of glass fiber.