Inhibitory activities of 264 methanol extracts, which were prepared from different parts of 210 kinds of wild and medicinal plants, against human thrombin were evaluated. Based on the anti-coagulation activity determined by thrombin time and activated partial thromboplastin time, the 14 extracts were screened. The fibrinolytic activity, heat stability and inhibition of other proteolytic digestive enzymes, such as pepsin, papain, trypsin and chymotrypsin, of the 14 extracts were further determined, and Ginko biloba (herba), Ephedra sinica (radix), Reynoutria elliptica (herba), Amomum tsao-ko Crevost (fructus), and Magnolia officinalis Rehd. et Wils (bark) were finally selected as possible plant sources for anti-thrombosis agent. These results suggested that medicinal and wild plants could be the potential source of thrombin inhibitor.