Objective:To provide a theoryetical guide for the clinical treatment, the changes of the hemodynamics during the process of the atherosclerosis spots and thrombosis were investigated. Methods: The vascular model were simulated by the ANSYS V5.4 software, and the vessel cavity were reduced progressively just as that of the artery in the atherosclarosis and thrombosis, the blood flow of the models in those conditions were analyses by the finite element method. The blood flow states in different viscositees were also observed by the method. Results: The blood flow in the normal vessels were laminar flow, the velocities were different in every stratum, the velocities were the fastest in the center and slow down towards the vessel wall. In the field where the vessel were narrowed, the dominant now were high speed laminar flow, and the speed were accelerated with the reducing of the vessels diameter. The blood flow became silted up in both side of the narrow field. When the viscocities come down, the high speed laminar flow were moved towards aistant heart side and the basis field changed. Conclution: From the study, it was suggested that through continuously ectatic treatment to the narrowed vessels, the treatment effect may be improved. It's necessary to study the meaning of the blood viscosity in the treatment of the disease.