OBJECTIVE：To establish a method for the content determination of total flavonoids in Morus alba. METHODS： UV-visible spectrophometry was performed with Al（NO2）3-NaNO2-NaOH color-test at the wavelength of 510 nm with the reference of rutin. RESULTS： The linear range of rutin was 0.031 2-0.156 mg/ml （r＝0.999 9）； RSDs of precision， stability and reproducibility tests were lower than 2％； recovery was 95.7％-101.0％ （RSD＝2.1％，n＝6）. CONCLUSIONS： The method is simple， stable and reproducible， and can be used for the content determination of total flavonoids in M. alba.