Chemical constituents of the stems of Canthium simile were studied.Seven compounds were isolated from ethyl acetate extract of the stem,and their structures were elucidated by various spectroscopic methods.They were identified as syringic acid(Ⅰ),isovanillic acid(Ⅱ),Caruilignan D(Ⅲ),(3β)-28-Norlup-20(29)-ene-3,17-diol(Ⅳ),3,4-dimethoxy-2,4-hexadienedioic acid(Ⅴ),dibutyl phthalate(Ⅵ) and diisobutyl phthalate(Ⅶ).The seven compounds were isolated from this genus for the first time.