The theoretical model for wet steam condensation flow was established. Furthermore, numerical simulation results with wet steam condensation flow model were coincident to the experimental data of C.A.Moses, which validated the credibility and accuracy of the model. Then, numerical simulation on condensation flow process was carried out under different configuration parameters. The results show that appropriately reducing the convergence ratio ?, area ratio and increasing the ι/d of secondary throat can increase the total pressure recovery coefficient，which improves the ejector performance.