Abstract: According to the thermodynamic model of formation of the solutions containing alcohol proposed in this work, an equation of excess volume was established by adopting the approach to releasing and charging attractive potential energy between two components.It indicated that the excess volumes of solutions containing alcohol were mainly dependent on changes of enthalpies caused by the dissociation of components and cross-association between them and attractive potential energy released or charged in this model. This equation showed good generality and was not only applicable to the solutions containing alcohol, but also to the solutions not containing alcohol. Extensive test proved that it could be used to correlate experimental data of variation of excess volume with composition for all kinds of binary liquid mixtures satisfactorily.