This standard specifies a method for determining the viscosity of polyvinyl chloride (PVC) (PVC) Resin in dilute solutions using a Capillary Viscometer. Viscosity is an important indicator reflecting the molecular weight of polymers and the rheological performance of solutions, and is of great significance for the quality control and application performance evaluation of PVC Resin. The standard specifies the test equipment, solvent selection, sample preparation, operation steps and viscosity calculation methods to ensure the accuracy and repeatability of test results.