The density (rho) and viscosity (eta) of poly(ethylene glycol) 300 (PEG300) + 1,2-ethanediol (1,2-ED), 1,2-propanediol (1,2-PD), 1,3-propanediol (1,3-PD), 1,3-butanediol (1,3-BD), or 1,4-butanediol (1,4-BD) binary liquid mixtures at temperatures of 298.15, 303,15, 308.15, and 313.15 K and refractive indices (nD()) at 298.15 K were measured over the entire concentration range at atmospheric pressure (0.1 MPa). According to the above measured values, calculation of a large number of thermophysical properties including the excess molar volume (V-m(E)), partial molar volume ((V) over dot(mi)), coefficient of thermal expansion (alpha(P)), refractive index deviation (Delta(nD)), viscosity deviation (Delta(eta)), and excess Gibbs energy of activation for viscous flow (Delta(G not equal E)) was performed. Finally, the Redlich-Kister polynomial equation was considered to estimate the interaction parameters by fitting the values of excess properties.