Objective: To investigate the chemical constituents and anticoagulant activity of Qin-Lian-Si-Wu decoction.Methods: Qin-Lian-Si-Wu decoction was extracted by hot-water

and then concentrated by decompression

and added ethanol till the concentration. of ethanol reached 80%.The upper solution was concentrated at（40 ℃

） dissolved by distilled water

separated by gradient elution with different concentration ethanol from macroporius adsorptive resins D101

then obtained the different fraction.Its constituents were isolated by silica gel column chromatographic method

and their structures were identified through UV

IR

NMR and MS spectrum.These compounds were prepared into aqueous solution

and then their effects on the blood plasma thrombin time in vitro in rabbits were determined.Result: Five flavonoids

one alkaloid

three aromatic acids

one sesquiterpene and two other components were isolated and identified from Qin-Lian-Si-Wu decoction.The results of thrombin time test showed that flavonoids

aromatic acids

alkaloid

sesquiterpenes could prolong the blood plasma thrombin time in vitro in rabbits remarkably.Conclusion: 12 compounds were isolated and identified from Qin-Lian-Si-Wu decoction for the first time.Nine compounds

including oroxylin A

wogonin

6-dimethoxy wogonin

berberine

baicalein

ferulic acid

vanillic acid

caffeic acid

rehmapicrogenin showed the anticoagulant activity at a certain dosage.