In this work, we report the measurements of the thermodynamic properties of RbF or CsF in the ethene glycol + water system at 298.15 K in the range of w = 0.10 to 0.40 ethene glycol. The experimental data were calculated by Pitzer model. Standard cell potentials and Pitzer parameters were obtained. From these, mean activity coefficients of RbF or CsF, osmotic coefficients of the mixtures, and standard Gibbs energies of transfer of RbF or CsF from water to ethene glycol + water mixtures were calculated.