Abstract: On the basis of the special conditions of dilute system at vapor liquid equilibria, an equation was proposed to relate the solubility of sparingly soluble gas in non-volatile solvent to temperature and pressure, by using the regular-solution theory and the Virial expansion for the Redlich-Kwong equa tion of state. The equation was used to correlate high-pressure gas solubility in non-volatile solvent at various temperatures. Compared with the Krichevsky-Ilinskaya equation, this method gave better results and simpler calculation procedure.