The thermodynamic properties of novel natural deep eutectic solvents (NDESs) based on amino acids are of great importance in extraction of pharmaceutical compounds. In this work, the vapor-liquid equilibria (VLE) for the aqueous solutions of natural deep eutectic solvents (NDESs) containing {lactic acid/alanine}, {lactic acid/glycine} and {lactic acid/histidine} at 298.15 K and atmospheric pressure were determined, and water activity is measured by using the isopiestic method. The obtained data then have been correlated with some activity coefficient models including nonrandom two-liquid (NRTL), Wilson, and universal quasichemical models (UNIQUAC). DFT method was utilized to evaluate the molecular interactions between the components of the investigated DESs and calculate the interactions energies.