Abstract: The pressure equalization process of miniature pressure swing adsorption (PSA) for oxygen generating was experimentally investigated by changing the switching pressure, pressure equalization time, ratio of height to diameter, inlet and outlet pressure of an absorber. The experimental results show that, under the experimental conditions, the oxygen purity increases first and then decreases with increasing switching pressure, and with the change in time of pressure equalization the best switching pressure is constant. As the time of pressure equalization increasing, the oxygen purity also increases at the beginning then decreases. There must be a best time of pressure equalization, which is decided by the absorber's structure. The bigger the ratio of height to diameter of the absorber is, the longer the best time of pressure equalization is. In the absorber of air flowing in, the pressure increases rapidly during the pressure equalization process, but its change is slow after the pressure equalization process. The pressure curves at the inlet and outlet are parallel.