The study data of SVTLEs which collected by the methods of biochemistry, molecular biology, bioinformatics and so on was summarized systematically in this article. Furthermore, SVTLEs’ categories and distribution, physic-chemical properties, enzymatic properties, structure features, gene cloning and expressions, and clinical application and so on have been reviewed in the paper. Then, we can find: SVTLEs mainly distribute between the venom of Viperidae and Crotalidae; SVTLEs are divided into three categories, namely, SVTLE-AB, SVTLE -A and SVTLE-B according to the different speeds of releasing fibrinopeptide A and fibrinopeptide B when SVTLEs hydrolyzed fibrinogen; many SVTLEs molecular weight are between 30 kD and 50 kD, have 6 disulfide bonds, and pI of most SVTLEs are lower, some are higher. SVTLEs could hydrolyze TAME and BAEE, their activity could be inhibited by DFP and PMSF, but their activity could not be inhibited by TLCK and EDTA - the specific inhibitors of trypsin and blood coagulation active center- histidine active center; Primary structure and secondary structure are more researched, and the higher structure will be the study emphasis in the future; most genes of SVTLEs are successfully expression in Escherichia coli, but they could not be glycosylated and right folded, therefore, SVTLEs’ biological activity is either lower or no active in the Escherichia coli expression system, but they are higher in the Eukaryotic expression system; some carbohydrates could stable structure and improve activity of SVTLEs and so on; SVTLEs have been extensively used in patients victims of myocardium infarct, ischemia stroke, thrombosis and so on. And we can make a conclusion that the expression of SVTLEs in the Eukaryotic expression system and the study of their higher structures will be the research emphasis in the future.