Fifteen compounds were isolated from the stem (with skin removed) of Sinocalamus affinis by a combination of various chromatographic techniques including silica gel, macroporous adsorbent resin, Sephadex LH-20, and preparative HPLC. Their structures were elucidated by spectroscopic data as ( + )-(1S, 2R)-1, 2-bis (4-hydroxy- 3-methoxyphenyl)-1, 3-propanediol (1), threo-guaiacylglycerol-beta-O-4'-coniferyl ether(2), erythro-guaiacylglycerol-beta-O-4'-coniferyl ether(3), ( + )-(7S, 8R, 8'R)-5'-methoxylariciresinol(4), ( + )-(7S, 8R, 8'R)-5, 5'-dimethoxylariciresinol (5), ( +/- )-glaberide I (6), ( - )-syringaresinol (7), ( - )-medioresinol(8), ( - )-(8R, 8R')-4, 4'-dihydroxy-3, 3', 5, 5'-tetramethoxyligna-9, 9'-diol(9), ( - )-secoisolariciresinol-9, 9'-acetonide (10), and ( + )-lyoniresinol (11); a new natural product 2, 6-dimethoxypyran4-one (12), and beta-sitosterol, 4-hydroxycinnamic acid, and 2, 6-dimethoxy-p-benzoquinone. These compounds were isolated from the genus Sinocalamus for the first time, compound 10 should be an artifact.