Abstract Viscometric behavior of polyvinyl alcohol (PVA) in NaCl/water solution ranged from dilute to extremely dilute concentrations was thoroughly investigated. Due to the influence of the adsorbed polymer on the walls of Ubbelohde viscometer capillary, an upswing of the reduced viscosity ( η sp/ C) vs. concentration ( C) curve was observed in extremely dilute concentration. If using improved viscosity measurement procedure to delete the influence of the adsorbed polymer upon the viscosity of polymer solution, the linear relationship between η sp/ C and C of PVA in NaCl/water solution was observed to exist, even in extremely dilute solution. Furthermore, the experimental results show that the improved viscosity measurement procedure presented in this article is not only a more reasonable but also a more convenient technique to determine the viscosity of polymer solution. The adsorption of polymer on the walls of viscometer capillary has been found to be greatly associated with the solvent in which the polymer was dissolved.