A high-pressure high-temperature dual-chamber facility is established for electrochemical impedance measurements of pressurized solid oxide fuel cells (PSOFC) to explain why and how the cell performance is increased with increasing pressure (p). By comparing two sets of nearly identical single-cell stacks except using different flow distributors with different degrees of flow uniformity at 850 degrees C over a range of p varying from 0.1 MPa to 0.5 MPa, we found that the better flow uniformity in flow distributors is, the better the cell performance is, and such performance enhancement is increased with increasing p. This finding is explained by impedance spectra and their associated equivalent circuit models, showing the coupling impact of flow uniformity and pressure elevation to the decrease of ohmic and polarization resistances. These results should be useful to the development of PSOFC integrating with micro gas turbines for future stationary power generation. (C) 2013 Elsevier B.V. All rights reserved.