Fifteen undescribed diterpenoid alkaloids and seven known analogs were coisolated from the whole plant Aconitum tanguticum (Maxim.) Stapf. Their structures were elucidated based on spectroscopic methods. Among them, tangirine A was a heteratisine-hetidine-type bis-diterpenoid alkaloid, tanguticinines A-F were six hetidine-hetisine-type bis-diterpenoid alkaloids, tanguticinine G was one hetidine-atisine-type bis-diterpenoid alkaloid, and N-oxide anthoroidine B, 5-deoxyanthoridine B and N-oxide 5-deoxyanthoroidine B were three unusual hetidine-rearranged hetisine-type bis-diterpenoid alkaloids. In the bioassay, thirteen compounds showed some inhibitory effects on the secretion of NO and TNF-α in LPS-treated RAW 264.7 cells, with IC50 values of 67.56 μM-683.436 μM.