A new excess Gibbs free energy/equation of state type mixing 0rule war derived by removing the infinite pressure boundary condition imposed Ly Wong and Sandler. The mixing rule was extensively tested in terms oi a comprehensive data base, consisting of 52 simple nonpolar-nonpolar, carbon dioxide containing, hydrocarbon-hydrocarbon, CFC, polar-polar, nonpolar-polar binary and multicomponent systems. focused on the complete predictive capability, a comparison between the Wong-Sandler and the mixing rule proposed was conducted. The results indicate that the new mixing rule is in general superior to the Wong-Sandler＇s, and the binary interaction parameter as required by the latter is removed, which reduces computing effort and is reliable in predictions of vapor-liquid equilibria rom low pressures Lo high pressures.