Interpenetrating polymer networks (IPNs) were prepared from polyurethane (PU) crosslinked epoxy and polyurethanes based on the mixture of polydiol and polytriol by the one-shot method. The mechanical properties, dynamic mechanical properties, morphology and damping behaviour were investigated. The results show that the damping ability and mechanical strength are enhanced through the introduction of PU cross-linked epoxy into the PU matrix to form the IPN structure. As the epoxy content increases, the tensile strength of the two types of the IPNs decrease in low composition, then increase in high composition. The damping properties of the PU (polyether type) cross-linked epoxy/PU IPNs are much better than those of the PU (polyester type) cross-linked epoxy/PU IPNs, but the mechanical properties reveal an opposite tendency. The sample with 20 wt% epoxy content in the PU cross-linked epoxy/PU IPNs shows particle-matrix morphology and exhibits good damping properties.