By the entropy density near the event horizon, the result has been obtained that the thermal radiation of the black hole satisfies the generalized Stenfan-Boltzmann law. The derived generalized Stenfan-Boltzmann coefficient is no longer a constant, but a proportional coefficient related to the black hole mass, the black hole charge, the average radial effusion velocity of the radiation particles near the event horizon, the cut-off distance and the thin film thickness. For an extreme Reissner-Nordström black hole, radiation energy flux and radiation power are all equal to zero. Then, the generalized Stenfan-Boltzmann law will lead to a black hole remnant. In this paper, we have put forward a thermal particle model in curved space-time. By this model, the thermal radiation of the Reissner-Nordström black hole has been studied. The result shows that when the thin film thickness and the cut-off distance are both fixed for the Reissner-Nordström black hole, the radiation energy flux received by observer far away from the Reissner-Nordström black hole is proportional to the average radial effusion velocity of the radiation particles, and inversely proportional to the square of the distance between the observer and the black hole.

Applying the entropy density near the event horizon, we obtained the result that the radiation energy flux of the black hole is always proportional to the quartic of the temperature of its event horizon. That is to say, the thermal radiation of the black hole always satisfies the generalized Stefan-Boltzmann law. The derived generalized Stefan-Boltzmann coefficient is no longer a constant. When the cut-off distance and the thin film thickness are both fixed, it is a proportional coefficient which is related to the black hole mass, the kinds of radiation particles and space-time metric near the event horizon. In this paper, we have put forward a thermal particle model in curved space-time. By this model, the result has been obtained that when the thin film thickness and the cut-off distance are both fixed, the radiation energy flux received by observer far away from the Schwarzschild black hole is proportional to the average radial effusion velocity of the radiation particles in the thin film, and inversely proportional to the square of the distance between the observer and the black hole.

By the statistical entropy of the Dirac field of the static spherically symmetric black hole, the result is obtained that the radiation energy flux of the black hole is proportional to the quartic of the temperature of its event horizon. That is, the thermal radiation of the black hole always satisfies the generalised Stenfan-Boltzmann law. The derived generalised Stenfan-Boltzmann coefficient is no longer a constant. When the cut-off distance and the thin film thickness are both fixed, it is a proportional coefficient related to the space-time metric near the event horizon and the average radial effusion velocity of the radiation particles from the thin film. Finally, the radiation energy fluxes and the radiation powers of the Schwarzschild black hole and the Reissner-Nordström black hole are derived, separately.