The GB/T 10339-2018 standard describes the determination of light scattering and light absorption coefficients of paper, Cardboard and pulp using the Kubelka-Munk method. The standard is applicable to various paper products. Optical inspection properties of samples, including their scattering and absorption characteristics, are analyzed by the Kubelka-Munk model. The standard provides detailed test steps, equipment requirements and data processing methods to ensure the accuracy of measurement results. This method helps to evaluate the Optical Properties of paper materials, supporting the optimization of product mass and application performance.