Fiber film extractor is novel high-efficiency equipment for two-fluid mass-transfer.In this paper，the kerosene-benzoic-acid-water was used as the experimental mass-transfer system.Under two different liquid distributor，varying the packed density of fibers from 1.89% to 5.08% and the flow ratio from 3 to 6，the performance of the fiber-film extractor was investigated on a cold model that made of 70 mm-ID，2630mm-height plexiglass pipe.The experimental results show that the optimal packed density of fibers is 3%—3.5% under different liquid distributors，feeding sequences as well as flow ratios.The optimal packed density corresponding to “feeding kerosene first” is somewhat less than that to “feeding aqueous benzoic acid first”. Based on the cold model experimental results as well as the maximum Reynolds number，a fiber-film extractor for caustic treating a 0.01 Mt·a-1 stream of RFCC gasoline was investigated.The industrial side-stream experimental results indicate that the efficiency of the fiber-film extractor for demercaptan is distinctly higher than that of the traditional apparatuses.