Objective Two-dimensional symmetrical models are used to simulate the steady flow in the AAA models.Methods A commercial CFD software FLUENT v4.3.2 is used for the flow simulation of AAA models.Results The velocity vectors,streamlines,wall shear stresses and pressure drops in AAAs are examined.Reynolds number and diameter ratio which affected the flow pattern and wall shear stress in the aneurysm are dealt with.Conclusion The results show that the shape of AAA and the D/d ratio have little effect on the flow patterns but the increases of Reynolds number would strengthen the vortex within the AAA.