The PVDF membranes were modified with surface coating (MC) and incorporation of superparamagnetic particles (MM) for the oxygen separation from water. It has been demonstrated that the preparation method has an influence on the membrane morphology which related to the O-2 separation performance. The morphology, magnetic property, and oxygen transport behavior of the PVDF, MC and MM were systematically investigated. The scanning electron microscopy revealed an asymmetric structure for all prepared membranes, and the MC and MM's surface defects. The total gas permeation from air increased with an increase of membrane pore size and porosity in the order of PVDF < MM < MC. It is found that the oxygen separation from air was not affected by an external magnetic field for MM and MC membranes. However, in the case of oxygen separation from water, the presence of the external magnetic field increased the oxygen mass transfer coefficient about 19% for MM and 32% for MC in average compared with PVDF. Among the membranes, the MC shows the highest value for both the oxygen permeance from air (3105 GPU) and the oxygen mass transfer coefficient from water (4.9 x 10(-3) cm/s).