Abstract: Objective To study the efect of spirulinakinase(SPK)extraction on thrombus formation and to explore its anti-thrombus formation mechanisms.Methods The coagulation time(CT)were compared between SPK group and control group with capillary vessel and sheet glass after SPK was injected in travenously into the rats.After add ingcerta inconcentration of SPK extraction solution to the plasma in vitro and injecting SPK extraction solution in to femoral vein,the activated partial thrombop lastin time(APTT),prothromb in time(PT)and thromb in time(TT)were tested.Results Due to the use of SPK extraction,the CT of the rats was significantly prolonged;the PT,the APTT and the TT were elongated.Conclusion The SPK extraction shows an obvious anti-coagulation effect in rats.