Hydrodynamic characteristics in shell side of a heat exchanger with alternating elliptical axis tubes are investigated numerically in present study. A two-dimension incompressible flow model is developed using unsteady Navier-Stokes equations and k − ε turbulence model for the analysis of fluid field, solved by finite element method. For given calculating conditions, such as shell diameter of unit duct, elliptical tube dimensions, arranging style and so on, the velocity and pressure contour , pressure drop between inlet and outlet, and energy distribution at different Reynolds numbers were obtained, they are very significant for the design of efficiency heat transferring exchangers.