Abstract: Objective To compare the different extraction methods for anticoagulant active substances from two kinds of Pheretima to obtain the best method. Methods Six methods were applied to extract anticoagulant activity substance from two kinds of Pheretima ，including water decocting method，0. 9% NaCl solution decocting method，70% ethanol reflux extraction，water decocting after degreasing with petroleum ether，0. 9% NaCl solution decocting after degreasing with petroleum ether，70% ethanol reflux extraction after degreasing with petroleum ether，and detected the activity of the substance with thrombin titration method. Results With the Whitmania pigra as positive control group，after being compared with blank and negative control group，the results showed the extracts from two kinds of Pheretima expressed anticoagulant activity under the six extraction methods. Among these six methods，the anticoagulant activity extracted with 0. 9% NaCl solution decocting after degreasing with petroleum ether was strongest. Conclusion The anticoagulant activity of extracts from different kinds of Pheretima are associated with pre-treatment and extraction methods. The degreasing with petroleum ether is in favor of the extraction.

Key words: different kinds of dried Pheretima, extraction methods, anticoagulant activity, thrombin titration method