Aim: To investigate the chemical constituents from the whole plants of Phlegmariurus fargesii. Method: Compounds were isolated by repeated silica gel column chromatography. Their structures were elucidated by spectroscopic methods and chemical correlation. The acetylcholinesterase (AChE) inhibitory activity of the isolated compounds was evaluated. Results: A new Lycopodium alkaloid, lycopodine N-oxide ( 1), along with lycopodine ( 2), 8,15-dehydrolycopodine ( 3), 6α-hydroxylycopodine ( 4), deacetyllycoclavine ( 5), N-methylhuperzine B ( 6), lycodine ( 7), and phlegmarine ( 8), was isolated. Conclusion: Compound 1 is a new Lycopodium alkaloid, and compound 3 was obtained from nature for the first time. Other alkaloids are isolated from this plant for the first time. © 2014 China Pharmaceutical University.