Abstract: The high Re number k-ε model and boundary condition of wall function method were applied to compute the turbulent heat transfer characteristics of liquid sodium flow in an annular tube.The numerical results are in good agreement with some experimental results in open literatures.Meanwhile,the turbulent heat transfer characteristics which is influenced by factors of the turbulence,heat condition and geometry size were studied.The analysis results indicate that: the influence of the turbulence was mainly reflected in the forepart of the tube.As the molecule diffusion effect played a more important role gradually in the middle and posterior part,the heat transfer difference between different turbulence flows decreased gradually along the flow direction.The factors of initial temperature and heat flux have little effect on Nu number.The turbulent heat transfer increases as the gap size of the annular tube increases,and with the same gap size,as the internal diameter and external diameter increase,the heat transfer coefficient changes very little.