Abstract: The radiation heating on the base flange concerns the safety of the jointing switch in satellites. The node and network method and the IRTE method are used to calculate the radiative flux of the engine, the heat shield radiation and the plume radiation on the base flange and the jointing switch. The effects of the three radiation sources on the heating of the base flange and the jointing switch are compared. Also, the effect of parallel moving of the engine’s position on the radiative heating is studied. It is shown that the effect of plume radiation on the radiative heating of the base flange and the jointing switch is the smallest, while that of engine radiation is the most important. The radiation flux varies in a large range on the surfaces of the base flange and the jointing switch, which is the largest on the surfaces towards the front face of the engine, and the smallest is on the surfaces towards the head face of the engine. Parallel moving of the engine’s position backwards can reduce the maximum radiation flux on the base flange and the jointing switch remarkably.