GB/T 20150-2023 defines the light spectrum and standard erythema dose of erythema reference action. It specifies the specific range of the light spectrum of erythema action and details the degree of action of each band on the skin to produce erythema effect. The calculation method of defining the standard erythema dose involves key factors such as radiation intensity and time. The standard is applicable to the field of photobiology. It provides a unified scale for evaluating the impact of light radiation on human skin erythema. It helps researchers study the mechanism of light-skin action. It also provides an important basis for Sunscreen Product Research & Development, phototherapy equipment calibrating and related safety standards formulation.