In this study, we applied the Flash extraction (FE) for the first time to the extraction of active ingredients of Sidahuaiyao (including Rehmanniae Radix, Achyranthes Bidentatae Radix, Dioscoreae Rhizoma, and Chrysanthemi Flos), and the content of active ingredients (catalpinoside, ecdysterone, chlorogenic acid and diosgenin) was determined by HPLC, and compared with Soxhlet extraction (SE) and ultrasonic extraction (UE). The results show that under the same solvent ratio, FE is used to extract the largest amount of different active ingredients. Compared with SE and UE, the extraction amount increases by 20.8% -92%. It is demonstrated for the first time that using FE to extract the active ingredients from Sidahuaiyao produced the highest extraction efficiency. In addition, we evaluated the anticancer activities of the main components. Three cancer cells and one normal cells were used to detect the anti-proliferative activity by MTT assay. The results showed that diosgenin had the strongest inhibitory effect on MCF-7 cells with IC50 value of 19.28±0.36μM. In short, we optimized the extraction process of Sidahuaiyao, and evaluated the anti-cancer activity of the main components, which provided a scientific theoretical basis for the application of Sidahuaiyao.