A mathematical model for hydrogen recovery from a feed gas using a four-bed, ten step PSA system, is proposed. Methane and Carbon Monoxide is the impurities of the feed gas from which hydrogen is recovered. The numerical solution of the proposed model resulted in pressure, concentration and velocity profiles within the beds. Finally, the effect of some important parameters such as adsorption pressure, cycle time, etc. are discussed and the optimum operational condition for this separation process is suggested.