Standard GB/T 38691-2020 specifies the test method for determining the specific surface area of petroleum refining catalysts. The standard applies to all types of petroleum refining catalysts, including Adsorbent and Auxiliaries, and aims to evaluate the key parameters of their activity and performance. The test method is based on nitrogen adsorption method, which covers the detailed provisions of sample preparation, experimental condition setting and data processing to ensure the comparability and Reliability of test results. The use of this standard requires attention to safe operation, and equipment calibrating and laboratory environment control according to the requirements of the standard to ensure the accuracy of the experimental process and the credibility of the data.