The α and β phases in Cu-Zn alloy system were regarded as regular solutions at elevated temperature, the results calculated from the experimental data have showed that the value of the interaction parameter of components Cu and Zn in the α phase E varied obviously with decreasing component Zn. Substituting the function relation between E and Xzn obtained through curve-fitting into expression of free-energy variation of the system, the calculated martensitic transformation temperature M was in good agreement with experimental curve, so as to have more comprehensive information for fully making use of binary Cu-base functional materials The α and β phases in Cu-Zn alloy systems were as regular solutions at elevated temperature, the results calculated from the experimental data have showed that the value of the interaction parameter of components Cu and Zn in the α phase E varied obviously with decreasing component Zn. Substituting the function relation between E and Xzn obtained through curve-fitting into expression of free-energy variation of the system, the calculated martensitic transformation temperature M was in good agreement with experimental curve, so as to have more comprehensive information for fully making use of binary Cu-base functional materials