The partitioning of membrane protein and liquid-liquid equilibria for Triton X-100-salt-water aqueous two-phase systems were measured at 293.15 K. A generalized model was proposed to predict both partitioning of membrane protein and phase behavior of the surfactant aqueous two-phase systems. By using part of liquid-liquid equilibria (LLE) data, Triton X-100-Na2SO4 and Triton X-100-Na2CO3 aqueous two-phase systems were successfully predicted. The results showed that most of the average absolute deviations were less than 1.0% (w/w). The partition coefficient of membrane protein in Triton X-100-Na2SO4 and Triton X-100-Na2CO3 aqueous two-phase systems were also successfully predicted. The results showed that most of the average absolute deviations of the two systems were less than 5% and 8%, respectively. The model could give good representation of partitioning of membrane protein and the phase diagrams. (c) 2005 Elsevier Ltd. All rights reserved.