The oxygen in-diffusion, out-diffusion, and permeability of layered perovskite-type-like YBa2Cu3O7-x (YBCO) were investigated by thermogravimetry, oxygen static adsorption, and oxygen permeability experiment. The results show that the oxygen in-diffusion at higher oxygen partial pressure is very faster, while the oxygen out-diffusion at lower oxygen partial pressure is relatively slow due to the formation of surface barrier. Oxygen permeation rate increases with temperature and arrives at 3.36 x 10-(7) mol/s cm(2) at 900degreesC for a YBCO membrane with thickness 1.00 mm. (C) 2004 Elsevier B.V. All rights reserved.