Abstract: A series of interpenetrating polymer network (IPN) materials, based on a rosin-based epoxy resin (RER) and a turpentine-based polyurethane (TPU) were prepared from gum rosin and turpentine oil. FT-IR spectra showed that the curing rate of the turpentine oil-based polyurethane was faster than that of the rosin-based epoxy resin and these two networks formed more sequentially than simultaneously in the final IPNs. The results of DSC showed that there was no phase separation in the final IPNs and each of the IPNs exhibited a single, broad glass transition temperature. When the rosin-based epoxy resin was 13% by weight, Tg reached the top value. The results of performance tests also showed that when the rosin-based epoxy resin was 13% by weight, IPN exhibited the optimum mechanical properties.