The oxygen permeation of dense U-shaped perovskite hollow-fiber membranes based on Ba0.5Sr0.5Co0.8Fe0.2O3-delta prepared by a phase inversion spinning process is reported. The perovskite hollow fibers with totally dense wall were obtained with the outer diameter of 1.147 mm and the inner diameter of 0.691 mm. The dependences of the oxygen permeation on the air flow rate on the shell side, the helium flow rate on the core side, the oxygen partial pressures, and the operating temperatures were experimentally investigated. According to the Wagner theory, it follows that the oxygen transport through the U-shaped hollow-fiber membrane is controlled by both surface reaction and bulk diffusion at the temperature ranges of 750-950 degrees C. High oxygen permeation flux of 3.0 ml/(min cm(2)) was kept for about 250 h at 950 degrees C under the conditions of the air feed flow rate of 150 ml/min and the helium flow rate of 50 ml/min. (C) 2010 American Institute of Chemical Engineers AIChE J, 57: 975-984, 2011