A novel C(17)N Lycopodium alkaloid (LA), lycoplanine B (1), containing an unusual formyl group, along with two new LAs, lycoplanines C (2) and D (3), were isolated from the whole plant of Lycopodium complanatum. Their structures were elucidated by extensive NMR techniques, including 1D- and 2D-NMR experiments, as well as comparing their spectral data with those of the known analogues. A possible biogenetic pathway for 1 was also proposed.