Abstract: EP-g-PU IPN was prepared by isocyanate terminated PU. AO-60/EP-g-PU IPN was prepared by adding AO-60.The processing,molecular structure, dynamic mechanical properties and morphology were studied by FTIR, DMA and SEM, and their mechanical properties were also tested. Results showed that: the damping properties of AO-60/EP-g-PU IPN were improved due to the strong hydrogen bond between AO-60 and PU molecular chain, but the mechanical properties of composites were reduced with AO-60 content increased because of toughening effect and particle aggregation; when mass ratio of AO-60 to EP was 0.4, damping properties and mechanical properties were optimized; it could be used as structural damping materials.