Abstract: AIM: To determine the contents and investigate the existence of isosteroidal alkaloids (ebeiedine, ebeiedinone, verticine, isoverticine, verticinone and imperialine) in 16 different Fritillaria species. METHODS: Samples were pre derivatized by trimethylsilylimidazole, and analyzed using gas chromatography. RESULTS: Sixteen different Fritillaria species studied in present paper were classified into 4 groups according to the existence and the structure type of the alkaloids determined in each species; (1) Only containing those 5α cevenine isosteroidal alkaloids (verticine, verticinone, ebeiedine etc.) whose hydrogens of C 13 and C 17 being at the state of trans configuration (e.g.F.thunbergii, F.hupehensis etc.); (2) Only containing those alkaloids (imperialine) whose hydrogens of C-13 and C-17 being at the state of cis-configuration (e.g. F.pallidiflora); (3) Containing both types of alkaloids (verticine, verticinone and imperialine etc.) whose hydrogens of C 13 and C 17 being at the state of trans- or cis-configuration (e.g. F.cirrhosa); and (4) No alkaloid mentioned above was detected at the present conditions (e.g.F.meleagroides). CONCLUSION: The resnets showed that the type and content of isosteroidal alkaloid varied in different Fritillaria species. This provided scientific evidence for the clinical use of these crude drug Beimus.