Abstract: In the study, the total content of flavonoid in Herba cirsii and Herba cirsii carbonisatus was determined by spectrophotometry. The result indicated that the regression equation was achieved, the linear correlation was from 0.008 to 0.048 mg/mL, the average recovery was 98.9%. The conclusion could be made that the method is scientific, and which could be used as one of standards to evaluate the quality of Herba cirsii and Herba cirsii carbonisatus.