An efficient Monte Carlo simulation approach for the study of fluid mixtures, the stepwise sampling method, is proposed. This method is carried out by changing the identity of particles in a system one by during the simulation, so that all the composition region can be studied, and all the excess properties of the mixture in the whole composition range can be estimated efficiently and accurately. Three Lennard-Jones binary system have been studied with this method. The results agree well with those obtained by Nakanishi with umbrella sampling method.,

Key words: THERMODYNAMIC PROPERTIES