This paper applies Peng-Robinson equation of state to the calculation of the thermodynamic properties and vapour-liquid equilibrium of refrigerant mixtures with a focus on non-azeotropic refrigerant mixtures R22/R114 and R13B1/R152a, azeotropic refrigerant mixtures RS00 andR502 because of their wide application. It shows that PR equation of state can be used to predict the bubble-point pressures and the vapour-liquid equilibrium as well as the liquid volumes of azeotropic refrigerant mixtures. For non-azeotropic refrigerant mixtures, e, g. R22/R114, the deviation for liquid volumes is a bit larger, but it still can meet the demands of engineering application in general. The results, compared with expermental data, are highly satisfactory.