The density and surface tension for the aqueous solution of the ionic liquid (IL) 1-hexyl-3-methylimidazolium acetate [C(6)mim][OAc] with various molalities were measured at T = (288.15 to 318.15) K with an interval of T = 5 K. On the basis of Li's model, as a new concept, the molar surface Gibbs energy of the ionic liquid solution was put forward and it was used to predict surface tension of aqueous [C(6)mim][OAc]. The predicted values of the surface tension are highly correlated and extremely similar to the corresponding experimental values. It is worth noting that the molar surface Gibbs energy can be connected with the volume, density and surface tension. Therefore, it can be developed as a semi-empirical method to predict physical properties of substances like the parachor. In terms of the molar surface Gibbs energy, a new linear Eotvos equation is obtained. Using this new equation, the values of the molar surface enthalpy for aqueous [C(6)mim][OAc] and other aqueous ILs were calculated. The results show that in the solution of the given molality, the molar surface enthalpy is a temperature-independent constant. (C) 2016 Elsevier Ltd. All rights reserved.