Abstract: A method for the determination of meisoindigotin in crude drug and tabletsts byreversed phase HPLC using daidzein as internal standard is described.The column employed waspacked with l0μm YWG-80(250 mm×4 mm),the eluting solvent consisted of methanol-water(80:20v/v)and the effluent was monitored at 254 nm.The experimental results showed that the contents of meisoindigotin in crude drug determined byUV spectrophotometric method and RP-HPLC are similar,so,the method can be used to controI thequality of the drug.