A series of Polyurethane (PU)/bisphenol A based Epoxy Resin (EP) Interpenetrating Polymer Networks (IPN) were synthesized and characterized by SEM, DSC, TGA and DMTA. It was found that IPN shows the best compatibility and damping properties when the ratio of PU/EP is 80 to 20. The results show that chain-extender and higher molecular weight of PPG are able to improve the properties of compatibility, damping and thermal properties.