The preparation of p-aminophenol from nitrobenzene by one-pot catalytic hydrogenation and in situ acid-catalyzed Bamberger rearrangement was first realized in a pressurized CO2/H2O system. By employing Pt鈥揝n/Al2O3 as catalyst, nitrobenzene could be converted to p-aminophenol with selectivity as high as 85% when the reaction was carried out at 140 掳C under 5.5 MPa CO2 and 0.2 MPa H2. This new protocol is environmentally benign because it is fully rid of the use of mineral acid by the application of self-neutralizable carbonic acid.