To develop an efficient extractor, a falling-film contactor with polypropylene hollow fibers as packing materials was used to extract phenol and acrylic acid from an aqueous phase with kerosene containing 30% (v/v) tributyl phosphate (TBP). The two fluids were added to the top of the extractor and due to the different affinity of the two phases, the organic phase would spread to a thin film on the fiber surface and the aqueous phase would spread on the organic phase, mass transfer could occur during the falling process. The flow characteristics in the extractor were studied with a theoretical model, by which the flow status in the module can be predicted and provide a way to select suitable membrane materials for a specified extraction system. Studies on the mass transfer characteristics showed that failing-film extractor using hollow fiber as packing is highly efficient because of a very large mass transfer area and can be operated at extreme phase ratios in comparison with an extraction column. © 2005 Elsevier B.V. All rights reserved.