Segmented polyurethane (SPU)/poly(vinyl chloride) (PVC) blends were particulated with gamma -Fe2O3. Interfacial properties of the composite were studied through the adsorption behaviors of SPU and PVC and their blends on gamma -Fe2O3 particles surface. Mechanical properties of the composite were measured with dynamic mechanical analysis and tensile test measurements. PVC with functional groups (FPVC), because of strong interactions, showed preferential adsorption on gamma -Fe2O3 compared with SPU and PVC. Moreover, the gamma -Fe2O3 particles were covered by FPVC in the gamma -Fe2O3/SPU/ FPVC composite. The adsorption layer of FPVC protected SPU from catalytic degradation by gamma -Fe2O3, resulting in increasing hydrolytic stability for SPU.