A thrombus is a mass formed from the constituents of the blood within the vessels or the heart during life. The process of its formation is known as thrombosis, It has been generally accepted that Holotrichia is an useful medicine for thrombosis. The rate of fibrinolysis of Holotrichia extracts increase as incubation times. Especially 52 days, the effect on the extracts has an maximum increased fibrinolytic activity, Heat-and-pH-stability of the extract on fibrinolysis is relative to temperature, At $37^{circ}C$, it has activating effect between pH 4 and pH 12. At higher temperature, especially $80^{circ}C$, an excessive increase in temperature has a deactivating effect on the extracts. Optimal pH of the extract on fibrinolysis is between pH 7.0 and pH 8.5, it is effective within a relatively broad pH range. In experiments of various inhibitors of Holotrichia extracts fibrinolytic activity, there are strong inhibitive effect on SBTI and Aprotinin, and a few inhibitive effect on DFP and t-AMCHA, no effect on PSMB and TLCK. Holotrichia extracts mixing with fibrinogen are observed Electron microscopy. it shows partially erosive-shaped fibrinolytic activity. In a SDS-PAGE of the extract having the fibrinolytic activity, three bands are found, protein 1, 2 and 3 having a molecular weight of 30,000, 45,000 and 60,000 Dalton.