Aim: To study isoquinoline alkaloids of the rhizoma of Coptis chinensis. Methods: Column chromatographic techniques were used for the isolation and purification of chemical constituents of the plant. The structures were elucidated by spectroscopic methods. Results: Seven isoquinoline alkaloids, 8-oxyberberine (1), 8-oxocoptisine (2), 8-oxo-epiberberine (3), 6-([1,3] dioxolo [4,5-g] isoquinoline-5-carbonyl)-2,3-dimethoxy-benzoic acid methyl ester (4), corydaldine (5), noroxyhydrastineine (6) and 6,7-methylenedioxy-1(2H)-isoquinolinone (7) were isolated from this plant. Conclusion: Compounds 1 ∼ 7 were isolated from this plant for the first time.