Abstract: A generalized method was presented for calculating the vapor-liquid equilibria of aqueous volatile weak electrolyte systems. By extending the KZ algorithm of simultaneous chemical and phase equilibrium calculations developed 玝y Xiao et al. (1989)to electrolyte systems with the electroneutrality equation being replaced by mass balance equations of ionic species, and splitting the complex system of dissociation reactions into two simple ones, the present approach showed better efficiency than those developed by Sanderson and Chien (1973) and by Gautam and Seider (1979). The calculated results agreed well with the experimental values.