Abstract: Six Lycopodium triterpenoids were isolated from Huperzia serrata. (Trev). Five of these were identified as 21-episerratenediol-3-acetate (Ⅱ), serratenediol-3-acetate(Ⅲ), 21-episerratenediol (Ⅳ), serratenediol (Ⅴ), and 16-oxodiepiserratenediol (Ⅵ). The sixth one is a new compound which was established as serratenediol-21-acetate(Ⅰ) by spectral analyses and preparation of derivatives