Eight alkaloids were isolated from the thin sulfuric acid extracts of the fresh roots of Stephania dentifolia by aluminum oxide, silica and Sephadex LH-20 column chromatography methods. Based on the spectroscopic analysis and chemical evidence, the structures of these alkaloids were identified as sinoacutine (1), sinomenine (2), cephamonine (3), tetrahydropalmatine (4), capaurine (5), stepharanine (6), (+)-stepharine (7) and palmatine (8). All compounds were obtained from this plant for the first time.