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As a new-type of liquid mineral resource of cesium including salt lake brine, geothermal water, underground water and seawater, the recovery of cesium is of great significance for its importance strategic purpose in modern industry, and the parameterization of ion-interaction model is essential to understand the ion-interaction of cesium borate solutions. In this paper, the dilution enthalpies on Cs2B4O7 aqueous solutions from 0.03900 to 0.54815 mol·kg−1 and CsB5O8 aqueous solutions from 0.02072 to 0.09889 mol·kg−1 at 298.15 K and 1.325 kPa were determined by the high-precision adiabatic microcalorimeter BT2.15 (Setaram, France), and the dissolution enthalpies for Cs2B4O7·5H2O and CsB5O8·4H2O were measured by the multi-channel microcalorimeter TAM-IV (TA, America). On the basis of experimental dilution enthalpies, the apparent molar enthalpies of Cs2B4O7 and CsB5O8 aqueous solutions were derived, and the diagrams of apparent molar enthalpy against molalities of Cs2B4O7 and CsB5O8 in aqueous solutions were plotted. And then, according to the Pitzer ion-interaction model of apparent molar enthalpy of electrolyte, Pitzer single parameters i.e. FMX ( β MX 0 L , β MX 1 L , β MX 2 L and C MX L , M = Cs+, X = [B4O5(OH)4]2− or [B5O6(OH)4]−) were obtained for the first time. The calculated apparent molar enthalpies for Cs2B4O7 and CsB5O8 aqueous solutions agree well with the experiment values, indicating that the single salt parameters obtained for Cs2[B4O5(OH)4] and Cs[B5O6(OH)4] in this work are reliable.