The paper reported the effect of fibrinolysin from Hunan Agkistrodon acutus on hemorheology in 23 cases of hyperviscosaemia and 31 cases of cerebral thrombosis. It is found that the flbrinolysin from Hunan Agkistrodon acutus may reduce low shear of blood specific viscosity, erythrocyte sedimentation rate (ESR),equation K value of ESR,and aggregative index of red blood cell, fibrinogen and plasma specific viscosity in patients with hyperviscosaemia and improve microcirculation of hyponychium in patients with cerebral thrombosis.This results indicate that the fibrinolysin may be used to treat these diseases.