A horsefly protease tabfiblysin isolated from the salivary gland of the horsefly, Tabanus Yao, a gene encoding the protease and use thereof are disclosed by the present invention. It belongs to the technical field of biomedicine. The molecular weight of the horsefly protease tabfiblysin is 27145.5 Daltons. Its full-length sequence is composed of 255 amino acids. Its encoding sequence is composed of 768 nucleotides. The horsefly protease tabfiblysin can hydrolyze fibrinogen and inhibit the aggregation of blood platelet dramatically, and can be used for preparing the drug for treating thrombotic diseases.
