Abstract: OBJECTIVE To study the chemical constituents from Corydalis Rhizoma and their quinone reductase(QR) inducing activties in vitro. METHODS Chromatographic and spectroscopic methods were used to isolate and identify the alkaloids from the ethanol extraction of Corydalis Rhizoma. QR induction assay was employed to investigate the QR inducing activities of the isolated alkaloids. RESULTS Nine compounds were isolated and identified as d-corydaline(Ⅰ), dehydroglaucine(Ⅱ), tetrahydropalmatin(Ⅲ), protopine(Ⅳ), α-allocryptopine(Ⅴ), tetrahydrocolumbamine(Ⅵ), dehydrocorydaline(Ⅶ), berberine(Ⅷ), palmatine(Ⅸ). Among these alkaloids, d-corydaline(Ⅰ) and tetrahydrocolumbamine(Ⅵ) possessed moderate QR inducing activities in vitro. CONCLUSION The QR inducing activities of alkaloids from Corydalis Rhizoma were investigated for the first time, and the results generally show a positive significance.