Abstract: This paper deals with the isolation and purification of hirudin from a bloodsucking leech, Hirudo nipponia in China. Essentially, the experimental process requires an anion exchange chromatography on DEAE-C52 and a gel filtration chromatography on Sephadex-G25. The hirudin activity were measured by the method of titration with thrombin. The salivary gland secretions have been obtained from the alive leeches. The hirudin content in salivary gland secretions is 4 AT-U/ml;the hirudin production rate is 15%; ratio activity after purifing is 6708 AT-U/ml protein.