Abstract: The growing interest in graft copolymers based on natural polysaccharides is associated with the wide range of their applications in medicine, particularly in ophthalmology. Samples of comb-shaped pullulan copolymer with side groups of poly(2-methyl-2-oxazoline) and poly(2-ethyl-2-oxazoline) are studied using molecular hydrodynamics methods. The influence of the molar mass of the initial pullulan on the properties of the resulting graft copolymers is studied. The conformational characteristics of graft copolymers, the grafting number of the side chains of poly(2-oxazoline) were obtained from the analysis of molecular hydrodynamic data.