Gas-liquid equilibrium (GLE) data were determined for dilute SO2 in the binary system poly ethylene glycol 300 (PEG) (1) + dimethyl sulfoxide (DMSO) (2) at T = 298.15 K and p = 123.15 kPa, and SO2 partial pressures were found from (0 to 122) Pa. The GLE compositions were determined with u(r)(C-SO2) = +/- 0.6 % for the liquid phase SO2 concentration and u(r)(z(SO2)) = +/- 5 % for the gas phase SO2 volume fraction. The measurement showed that dilute SO2 solubility in the PEG + DMSO mixtures decreased with the increasing PEG concentration. In the whole composition range, the pure DMSO showed the strongest solubility capability for dilute SO2 with 0.0756 mol.kg(-1) and the solubility of SO2 in PEG was 0.0100 mol.kg(-1) when the gas phase SO2 concentration (z(SO2)) was set at z(SO2) = 5.10(-4) In addition, the paper also reported densities and viscosities for the binary system PEG (1) + DMSO (2) as a function of composition. Based on the experimental density and viscosity data at T = (298.15 to 318.15) K, the excess molar volumes and viscosity deviations were calculated, and the calculated results were fitted to a Redlich-Kister equation to obtain the coefficients and estimate the standard deviations. Based on the kinematic viscosity values, enthalpy of activation for viscous flow and entropy of activation for the viscous flow were also calculated.