In this work, isothermal gas-liquid equilibrium (GLE) data are reported for the system of SO2 + N-2 + polyethylene glycol (PEG) 300 + water (H2O) at five different reaction temperatures (from 298.15 to 318.15K) and different pressures (from 110.34 to 142.03 kPa) with SO2 partial pressures in the range of 0 to 180 Pa. Measurements were carried out by a saturation method using a glass absorption apparatus, which was controlled at constant temperatures by a thermostatic circulation bath with a Beckmann thermometer. The GLE data were obtained with uncertainties within +/- 0.02 K for temperature, +/- 0.1 kPa for total pressures, and +/- 0.05 for SO2 concentration in the gas phase and +/- 0.003 for SO2 concentration in the liquid phase. The measurements showed that the solubility of dilute SO2 in the system of PEG (1) + water (2) increased the with increasing PEG concentration in the mass fraction range of w(1) = (0.50-1.00). The solubility of SO2 in the system of PEG (1) + water (2) presented an extreme minimum at the mass fraction of w(1) = 0.50 of 152.3 g m(-3) when SO2 in the gas phase was designed at y(SO2) = 5 x 10(-4). The solubility of dilute SO2 in the system of PEG (1) + water (2) increased with decreasing PEG concentration in the mass fraction range of w(1) = (0.05-0.50). The solubility of SO2 in the system of PEG (1) + water (2) presented an extreme minimum at the mass fraction of w(1) = 0.05 of 270.7 gm(-3) when SO2 in the gas phase was designated at y(SO2) = 5 x 10(-4). Henry's law constants were fitted with a dynamic system based on the GLE data. Using the solubility data, the partial molar thermodynamic functions of solution, enthalpy and entropy, were calculated. Conclusions drawn from this work may be used to provide important GLE data for the design and operation of the absorption and desorption processes of PEG solutions in flue gas desulfurization. (C) 2013 Elsevier B.V. All rights reserved.