In this study, the kinematic viscosity of water-polyethylene glycol-KI systems at a temperature of 20℃ and 0-0.05 molar fractions of KI and 0-5 g/dl of polyethylene glycol was studied and fractions of polyethylene glycol with molecular masses of 1000, 1500, 3000, 4000 and 6000 were taken. Based on the experimental values of the kinematic viscosity, the characteristic viscosity of the studied solutions in the considered concentration range of KI, the Haggins constant, the α parameter included in the Mark-Kun-Having formula, the swelling coefficient of the polyethylene glycol macromolecule, the characteristic viscosity in the θ-solvent, the chain of the polyethylene glycol macromolecule in the solution and the θ-solvent root-mean-square distance between ends, Kuhn segment length in solution and θ-solvent were calculated. It was determined that the polyethylene glycol macromolecule is in the form of a wash in the water-KI environment that the surrounding liquid can penetrate, and with the increase in the concentration of KI, the volume of this wash decreases and its mobility increases.