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.