A theoretical study on a combined power and ejector refrigeration Cycle using zeotropic mixture isobu tane/pentane is carried out.The parametric analysis of generator temperature, condenser tempera ture and evaporator temperature for all the mixtures shows that, all these three thermodynamic parameters have a strong effect on the cycle performance.And mixture isobutane/pentane (50/50) has the maxi mum exergy efficiency of 7.83%.