This standard provides general methods, conditions, and standard parameters for determining the reduced viscosity, intrinsic viscosity, and K-value of dilute solutions of organic polymers. It serves as the foundational part of this series of determination methods. When a specific polymer solution lacks a dedicated testing standard, this general rule can be followed for testing. The core of this method involves calculating viscosity parameters by measuring the flow rate of the solution under specific conditions. The primary instrument used in the experiment is a capillary viscometer, such as a Cannon-Fenske or Ubbelohde viscometer, which operates based on Boyle's law. To ensure measurement accuracy, the process must be conducted in a precisely controlled constant-temperature water bath to maintain highly stable solution temperatures. Additionally, a precisely graduated thermometer and a stopwatch are essential auxiliary tools for the measurement.