This paper constructs a model of refrigerant thermodynamic properties calculation for simulation of refrigeration and air condition system based on the parametric equations of state of refrigerant. The Visual C++ 6.0 language is used to develop this model, which has a friendly user interface (UI). This program is easy to learn and use and it has reliably function. Compared with the data provided by the standard graphs and tables of refrigerant thermodynamic properties, the calculation results of this model have certain precision and meet the expectative requirements.