Abstract: In order to investigate the heat and the mass transfer during pressure swing adsorption (PSA) for oxygen production and improve oxygen production efficiency, a gas-solid two-phase pressure swing adsorption model was established for the π-shaped centripetal radial flow adsorber (CP-π RFA). The energy model, the adsorption heat, and the particle diameter were comparatively studied using this model. The results show that the maximum temperature in the adsorbent bed during pressurization with air (PR) and high-pressure feed (AD) processes for the single-phase model are 309.19 K and 313.63 K, respectively. The highest oxygen mole fractions in the adsorbent bed during PR step and AD step using the single-phase model are 55.66% and 62.65%, respectively. Under the same operating conditions, the maximum temperature in the adsorbent bed during the PR and AD steps for the two-phase model are 302.27 K and 305.29 K, respectively. The highest oxygen mole fractions in the adsorbent bed during PR step and AD step using the two-phase model are 57.51% and 66.02%, respectively. For no-adsorption heat, the maximum temperatures are 293.5 K and 293.9 K, respectively, and the highest oxygen mole fractions in the adsorbent bed during the PR step and AD step with no-adsorption heat are 59.25% and 72.18%, respectively. However, the maximum temperature in the bed during the two steps with adsorption heat are 302.3 K and 305.3 K, respectively, and the highest oxygen mole fractions are 57.51% and 66.02%, respectively. As the particle diameter increases, the highest oxygen mole fraction of the outlet would decrease, while the oxygen flow rate and recovery would increase. The adsorbent with a particle diameter of 1.6 mm is the best size. The laws of the heat and the mass transfer in the adsorber can provide an important technical reference for CP-π RFA in the PSA for oxygen production.