Abstract: Dynamic mechanical analyses of EB-cured epoxy resin are made. Through the research on variation regularity of the gel fraction, damping factor and dynamic modulus for different samples, the influences of EB radiation dosage, initiator dosage and heating treatment on radiation curing reaction of epoxy resin were obtained. The gel fraction, glass transition temperature and high temperature modulus of the cured epoxy resin increase with the rising of radiation dosage and the increased extents are decrescent at high radiation dosage. The inhomogeneity degree of cross-linked structure is enhanced with the increasing radiation dosage. In low radiation dosage, the glass transition temperature and high temperature modulus of the cured epoxy resin increase with the enhanced initiator dosage. But when high dosage radiation is used, the optimal dosage of the initiator appears. When the EB-cured epoxy resin is heated, the cross-linking extent is enhanced. But when the temperature of heating treatment exceeds the thermal decomposition temperature of the initiator, the local cross-linking network formed from thermal curing reaction can exist in the resin system.