ASTM D7708-23a standard specifies a microscope method for the determination of disperse vitrinite reflectance in sedimentary rocks. This method is used to evaluate the thermal maturity of disperse organic matter in sedimentary rocks by microscope measurement of the reflectance of vitrinite polished surfaces in oil immersion. Vitrinite reflectance is an important indicator to measure the thermal maturity of sedimentary rocks, which can be used to characterize the changes of organic matter during diagenesis, pyrolysis and metamorphism. The standard is also applicable to the reflectance determination of Miscellaneous microscopic components, providing important technical support for geological research, oil and gas exploration and coal quality analysis.