Abstract: A 1∶10 2D model of radiation heat transfer and natural convection outside the 2D steel containment was established in this paper. The advanced computational fluid dynamic analysis software Fluent was applied to complete the calculation. The velocity nephogram and the velocity vector diagram on the head of steel containment were obtained, and the results show that there is an air stagnant zone on the head of steel containment. The influence of channel width, airflow speed and emissivity of wall surface on heat transfer was studied as well. The appropriate channel width and airflow speed can enhance the heat transfer and the efficiency of heat exchange. The increase of the emissivity of wall surface can obviously improve the radiation heat transfer on the head of steel containment.