Abstract: In order to find out the influences of inlet parameters on the two-component mixture spontaneous condensation flows,and to offer reference for industry application of supersonic separator,a mathematical model was developed to investigate the two-component mixture spontaneous condensation flow.A numerical simulation was performed for the two-component mixture in nozzle with the model. The comparison between numerical results and experimental measurement shows that the model is accurate.With the model the influence of different inlet parameters was investigated.It was found the liquid mass fraction became higher with the lower pressure,higher temperature or higher supersaturation at inlet for nozzle with certain expansion rate and length.It is useful to change the pressure,temperature and supersaturation at inlet properly to get higher separation efficiency in industry application.