AIM: To study the chemical constituents from the roots of Stephania dielsiana. METHODS: Various column chromatographic techniques were used for isolation and purification. The structures were elucidated on the basis of spectral data and chemical evidences. RESULTS: Eighteen compounds were isolated and elucidated as twelve alkaloids: sinoacutine (1), stephanine (2), ayuthianine (3), dehydrostephanine (4), cephamorphinanine (5), aknadinine (6), liriodenine (7), sinomenine (8), 1-tetrahydropalmatine (9), (-)corydalmine (10), oxocrebanine (11), norcanelilline (12), four lignans: gomisin A (13), gomisin B (14), schisandrin C (15), 6-O-benzoylgomisin (16), one oligopeptide asterinin B (17), and one sterol beta-Sitosterol (18). CONCLUSION: Fourteen compounds 3, 5-8 and 10 similar to 18 were isolated from the plant for the first time.