Supercritical CO2 fluid extraction (SFE) uses CO2 as the solvent and utilizes the relationship between the solubility of the supercritical fluid and its density, that is, the influence of pressure and temperature on the solubility of the supercritical fluid. In the supercritical state, the supercritical fluid is brought into contact with the substance to be separated, so that the components with polarity, boiling point and molecular weight can be selectively extracted in sequence. Supercritical extraction can be carried out at room temperature (35-40°C) and under a blanket of CO2 gas, which effectively prevents the oxidation and escape of heat-sensitive substances. The entire extraction process does not require organic solvents, has high purification, is easy to prepare, and can be used in It can be reused in production and can effectively reduce costs. Therefore, supercritical fluid extraction technology is a new green separation technology in chemical separation. Supercritical CO2 extraction is particularly suitable for the extraction of fat-soluble, high boiling point, heat-sensitive substances. It is also suitable for the fine separation of different components, that is, supercritical distillation. Supercritical CO2 is commonly used as a solvent for the extraction and purification of many products such as biology, food, and pharmaceuticals.