Abstract: In this Paper, a high performance liquid chromatographic method for the determina tion of quercetin in the extract of bluish dogbane was reported.A Shimadzu liquid chromatograph Lc-2 with a column (25cm×4.6mm) of YWG*CH (C₁₈ chemicaliy bonded stationary phase) was used.50% methanol containig 1.5% phosphoric acid was chosen as the mobile phase.Detect ion was at 254nm,The quantity of quercetin was determined by internal standard method with β-naphthol as a reference.The result showed that the mean content of quercetin in bluish dogbane was 0.17B with a standard deviation of 3.2%(eight determinations).The proposed method is simple, rapid and reproducible.