The new compound hemsleyatine (1) was isolated along with four known C(19)-diterpenoid alkaloids: indaconitine (4), yunaconitine (5), chasmanine (6), and talatisamine (7) from the roots of Aconitum hemsleyanum PRITZ. Structures were established by spectral analysis, including tow dimeusional (2D) NMR spectroscopy and a chemical method. Hemsleyatine (1) is the first C(19)-diterpenoid alkaloid bearing the 8-amino group. In addition, the assignments of some (13)C signals for pseudaconine (3) were revised by comparison with those of hemsleyatine (1).