Abstarct: Most of the veins in the body are curved vessels are known to be one of the causes of atherosclerosis. Vasoconstriction, narrowing the cross-sectional area of blood vessel happens due to this disease. Narrowing the vascular area significantly affects the normal hemodynamics of the bloodstream which can greatly affect the disease progression. During clinical observations, clogging has been reported in arteries of varying diameters. The plaques lead to cloggings with different lengths and percentages. A study on the dynamics of blood flow in the arteries with stenosis will provide a diagnosis of vascular diseases. In such areas, the flow is extremely complex and a proper understanding of current physics is not possible except by the dynamical examination of blood fluids. In the present thesis, the effect of dynamic parameters of blood flow on the different curvature ratios of the vessel, percentage and stonesis length ratio of the clog, and the blood concentration has been simulated by Fluent using a 3D tube with 90-degree curvature. The present study was conducted to investigate the effects of symmetric clogs at 25%, 50% and 75% of the vessel diameter, curvature ratios of 0.167, 0.093and 0.052, length ratio of stenosis 0.667, 0.5, 0.31, and power index changes on blood behavior. The results of this study indicate that the maximum outer wall shear stress for a vessel with 75% stenosis, stonesis length ratio of 0.667, and curvature ratio of 0.167 is 41.5 times bigger than the maximum outer wall shear stress of a sound vessel in the time of its maximum velocity of the systole. Also the maximum shear stress applied on the vessel with 50% stenosis, 0.167 curvature ratio, and stenosis length ratio of 0.31 is 7 times of the maximum shear stress on the wall of a sound vessel in the time of the maximum velocity of systole.