A new fluorenone alkaloid (caulophine) was isolated from the radix of Caulophyllum robustum Maxim. (collected from the Qinling mountains) using cell membrane chromatography as the screening method. Caulophine was identified as 3-(2-(dimethylamino)ethyl)-4,5-dihydroxy-1,6-dimethoxy-9H-fluoren-9-one based on physicochemic and spectroscopic analyses, particularly by NMR spectroscopic data (i.e., COSY, HMQC, HMBC, NOESY). Caulophine possessed anti-myocardial ischemia activity.