ObjectiveTo discuss the speciality of AlCl3 colorimetry with rutin as reference substance for evaluation on the content of total flavonoids and investigate the optimum condition of AlCl3 colorimetry.MethodsTo make a series of flavonoids and polyphenols with typical structure with AlCl3 and measure their absorption curves at the range of 200 ~600 nm.ResultsAt the wavelength of 421 nm,some flavonoid-like compounds showed the similar absorption with rutin.ConclusionIt is reasonable to determine the total flavonoids by using AlCl3 colorimetry with rutin as reference substance and establish the optimum condition of AlCl3 colorimetry.