In this work, a new activity coefficient model was deduced for the correlation of solid-liquid equilibrium (SLE) in electrolyte solutions. The new excess Gibbs energy equation for SLE contains two parts: the single electrolyte item and the mixed electrolyte item. Then a new hypothesis for the reference state of activity coefficients was proposed in the work. Literature data for single electrolyte solution and mixed electrolyte solution systems, with temperature spanning from 273.15 to 373.15 K, were successfully correlated using the developed model. (C) 2016 The Chemical Industry and Engineering Society of China, and Chemical Industry Press. All rights reserved.