In the low-opacity material, the coupling between radiant transport and electronic energy is strong. The system of radiant transport equation and electronic energy equation represents strong stiffness, which induces difficulties in numerical simulation. In this paper, an effective numerical method for the simulation of the strong coupling between radiant transport and electronic energy is introduced. This method is an integral method based on the ansatz assumption of the electronic temperature. There is no constraint on the time step. Thus the method has high computing efficiency and good accuracy.