Supersonic steam flow with spontaneous condensation is of considerable interest in several natural and industrial processes including cloud formation, flight of aircraft in humid conditions, supersonic steam flow in wind tunnel experiments, turbines and chemical industry equipment. In the present study, the supersonic steam flow with non-equilibrium phase change and condensation shock is numerical studied based on the computational fluid dynamics (CFD) method. A conservative compressible numerical model coupling with non-isothermal classical nucleation model and droplet growth model modified, in which the thermodynamic state and properties of steam are calculated by the Virial Equations, is developed and used to predict the spontaneous condensation phenomenon with homogenous nucleation in the supersonic steam jetting flow in the nozzle. The analysis of the boundary effects in the supersonic steam flow and investigation of the partition characteristics for the condensation X-Shock are accomplished. The thermodynamic and aerodynamic properties of both condensation shock and normal aerodynamic shock are studied and the difference between the condensation shock and the aerodynamic shock are investigated. The coupling effect mechanism of shock and non-equilibrium phase change in the supersonic steam flow is revealed.