The "GB/T 31225-2014 Method for the measurement of thin film thickness of silicon dioxide on silicon surfaces by elliptical polarizers" standard describes in detail the method for the measurement of thin film thickness of silicon dioxide on silicon substrates using Light spectrum type elliptical polarizers. The standard is suitable for testing thin layers of silicon dioxide with uniform and isotropic film thickness in the range of 10 nm to 1000 nm. The standard describes the process of measurement using elliptical polarized light technology, which includes the operating principle of continuously variable wavelength and variable angle to ensure accurate measurement of thin film thickness. In addition, the standard also defines related terms such as ellipsometry and Fresnel's reflection law, providing theoretical support for related measurement techniques.