Three new C(20)-diterpenoid alkaloids, along with twenty-two known alkaloids, were isolated from the whole herbs of Delphinium tatsienense. The new alkaloids include a vakognavine-type C(20)-diterpenoid alkaloid, designated as tatsienenseine A (1), and two hetisine-type C(20)-diterpenoid alkaloids, designated as tatsienenseines B (2) and C (3). Their structures were elucidated by IR, HR-ESI-MS, 1D- and 2D-NMR analyses.