Abstract: The supersonic 6-nozzle ejector performance has been investigated experimentally for the given geometric dimensions.The experiment ranges over 1.98≤P_p^*/P_s^*≤7.46,0.971≤T_p^*≤T_s^*≤1.02 and L_m/D_m=0.80.The entrainment ratio x varies from 6.96 to 11.66 for the ejector with a diffuser,and its corrected value x/√T_s^*/T_p^* varies from 6 88 to 11.62;on the other hand,the entrainment ratio varies from 2.82 to 6.28 for the ejector without the diffuser,and its corrected value varies from 2.78 to 6.24.The experimental results show that the entrainment ratio and its corrected value decrease with the increase of P_p^*/P_s^* ,but the corrected momentum coefficient K_m in the mixing pipe goes up.The mass flow rate coefficient μ of the primary nozzle increases slightly as the entrainment ratio goes up .The theoretical analysis has been done for the above conditions by application of aerodynamics.The comparison between the analysis and the experiment shows a good agreement.