GB/T 5527 - 2010 specifies the method of measuring the refractive index of animal and vegetable oils. The standard is based on the principle of refraction of light and stipulates the use of high-precision refractometers for measurement. Detailed instructions on the calibrating and maintenance requirements of the instrument to ensure the accuracy of measurement data. For animal and vegetable oil samples, the collection, pretreatment and homogenization operation steps are clarified. In the measurement process, there are strict regulations on temperature control, sample filling and reading methods. By implementing this standard, the refractive index of animal and vegetable oils can be accurately determined, providing a key basis for the identification and classification of oil quality and the production and mass control of related products.