Lycojapodine A, a novel C16N-type Lycopodium alkaloid with an unprecedented 6/6/6/7 tetracyclic ring system, was isolated from the club moss Lycopodium japonicum. The structure and relative stereochemistry were elucidated on the basis of spectroscopic data and were further confirmed by X-ray analysis. A possible biosynthetic pathway for 1 was proposed. Its inhibitory activity on acetylcholinestrease and anti-HIV-1 activity were also evaluated.