Abstract: The active constituents in semen pharbitidis were studied. Seperation and purification were performed on columns of silica gel and Sephadex LH-20, and the chemical structures were elucidated by various spectroscopic data. Eight compounds were isolated from ethyl acetate fraction of 70%(volume fraction) ethanol extract, and identified as cinnamic acid(Ⅰ),ferulic acid(Ⅱ),chlorogenic acid(Ⅲ),methyl chloroformate(Ⅳ),propyl chloroformate(Ⅴ),rhein(Ⅵ),12-hydroxy-methyl abieformate(Ⅶ) and 12-hydroxy-hydromethylabieformate(Ⅷ). These compounds were isolated from the genus Pharbitis for the first time by search.