Two new quaternary protoberberine alkaloids, namely corydayanine (1) and yanhusuine (2), were isolated from the tubers of Corydalis yanhusuo. On the basis of extensive chemical and spectroscopic evidences, especially 1D and 2D NMR and HRMS experiments, their structures were elucidated as 5,6-dihydro-3,9-dihydroxy-2,10-dimethoxy-13-methyl-dibenzo[a,g] quinolizinium alkaloid and 5,6-dihydro-12-hydroxy-2,3,9-trimethoxy-13-methyl-dibenzo[a,g] quinolizinium alkaloid, respectively.