The solubilities of salts and densities of equilibrium solution in the ternary systems KBr-CaBr2-H2O and NaBr-CaBr2-H2O at 348 K were determined with the method of isothermal solution saturation. On the basis of the experimental data, equilibrium phase diagrams in the ternary systems listed above were plotted, respectively. The solubility diagram of the ternary system KBr-CaBr2-H2O has one invariant point, two stable solubility isotherm curves, and two crystallization fields corresponding to CaBr2 center dot 2H(2)O and KBr. The solubility diagram of the ternary system NaBr-CaBr2-H2O includes one invariant point, two univariant curves and two fields of crystallization CaBr2 center dot 2H(2)O and NaBr. And the densities calculated from empirical equations are in good agreement with the experimental data. The dissolution equilibrium constant K for NaBr, KBr, CaBr2 center dot 2H(2)O in the ternary systems at 348 K were fitted by using the Pitzer equations and the multiple linear regression method. A chemical model was constructed to calculate the solubility data by using the Pitzer equations in the ternary systems KBr-CaBr2-H2O and NaBr-CaBr2-H2O at 348 K. The calculated solubilities are in agreement with experimental data.