To establish a method for the determination of total flavonoids in 18 species of Compositae from Qinghai Province,we used AlCl₃ colorimetry to determine the content of total flavonoids at 421 nm by UV spectrophotometry with rutin as control.The results showed that the linear regression equation y=0.022 6x+ 0.010 5 and R²=0.998 and the rutin concentration had a good linear relationship with absorbance in the range of 2-30 μg/mL.The precision,stability and repeatability were good.The content of total flavonoids in 18 species of Compositae in Qinghai ranged from 0.41 to 18.67 mg/g，the content of total flavonoids in two species of Anaphalis is the highest with an average of 15.72 mg/g.The method is simple,accurate and practical,which lays a theoretical foundation for further study and development of Compositae plants.