Abstract: The energy exchanging term between electron and radiation often makes the three temperature energy equations stiff at T_e~T_r region and causes difficulty in numerical simulation of laser-target coupling.In near local thermodynamic-equilibrium (LTE) region,the emission and absorption of radiation are large and nearly equal,which results in divergence of iteration.In order to solve this problem,this paper discusses a method in which different expressions of the energy exchanging term in non-LTE and nearly LTE regions are given.The energy exchange in near LTE case has been calculated by using Rossland mean free path,instead of bound electron population.