The XG equation, which is developed by us previously for describing the adsorption equilibrium of purevapor on activated carbon, is extended to multi-component system. Verified by experimental data, the extendedXG equation was found to be more successful in predicting the adsorption equilibrium of vapor mixture on activatedcarbon than the extended Langmuir equation, the extended BET equation and the ideal adsorbed solution theory(IAST).