An adsorption (PSA) unit consist of two – tubes columns pressure swing, (6cm diameter and 70cm bed length) and a dryer part (12cm diameter and 27cm) filling with activated alumina (Al2O3) have been constructed to study the separation of oxygen and nitrogen from air using commercial 5A zeolite under the effect of adsorption pressure (1 to 6 bar), adsorption time (20s), product flow rate (1 liter/min) on the product oxygen purity. For the case of 2-column, 4-step operation, the results show that an optimum concentration product of oxygen was 76.9%purity,at the adsorption pressure 4bar, Temp 17.4oC.Nitrogen optimum production was78.8% purity, at 1 bar