Abstract: Five alkaloids were isolated from the root of Stephania tetrandra S. Moore. Three of them were shown to be identical with tetrandrine (Ⅱ), fangehinoline. (Ⅳ), and cyclanoline (Ⅴ). The other two named oxofangchirine (Ⅰ) and stephenanthrine (Ⅲ), are new alkaloids, the structures of which were elucidated as Ⅰ and Ⅲ on the basis of spectral analysis, and the structure of oxofangchirine was established as Ⅰ by X-ray diffraction method also.