Abstract: Based on improved PSRK equation of state model，the simulation of industrial two-stage ammonia-water absorption refrigeration system was perfomed with the help of Aspen Plus software. Analysis of the process was made，and the best split fraction was presented. The change of ξ(coefficient of performance) with the concentrations of ammonia-water from high pressure absorption and low pressure absorption systems was deduced，and several methods to enhance the absorption were proposed.