Abstract: Based on Eyrings theory of viscosity of pure liquids, an equation for the calculation of the viscosity of liquid mixtures was proposed from the concept of local molar composition: where V represents the viscosity, V molar volume, ga interaction energy between the molecules of the same kind, ga interaction energy between the molecules of the defferent kinds, n, R, T, x have their conventional meaning, and the subscripts i, j denote -component and j-component respectively. By the use of this equation, thirty binary systems and five ternary systems were tested with satisfactory agreement between calculated and experimental values. This equation is, therefore, valid both for correlate viscosities of binary systems and predict those of multicomponent systems from binary parameters.