By using the entanglement entropy method, this paper calculates the statistical entropy of the Bose and Fermi fields in thin films, and derives the Bekenstein-Hawking entropy and its correction term on the background of a rotating and charged black string. Here, the quantum field is entangled with quantum states in the black string and thin film to the event horizon from outside the rotating and charged black string. Taking into account the effect of the generalized uncertainty principle on quantum state density, it removes the difficulty of the divergence of state density near the event horizon in the brick-wall model. These calculations and discussions imply that high density quantum states near the event horizon of a black string are strongly correlated with the quantum states in a black string and that black string entropy is a quantum effect. The ultraviolet cut-off in the brick-wall model is not reasonable. The generalized uncertainty principle should be considered in the high energy quantum field near the event horizon. From the viewpoint of quantum statistical mechanics, the correction value of Bekenstein-Hawking entropy is obtained. This allows the fundamental recognition of the correction value of black string entropy at nonspherical coordinates.

We extend the Damour-Ruffini method and discuss Hawking radiation of Kerr-Newman-de Sitter black hole. Under the condition that the total energy and angular momentum of spacetime are conserved, taking the reaction of the radiation of particles to the spacetime into consideration and considering the interrelation between the black hole event horizon and the cosmological horizon, we obtain the black hole radiation spectrum. This radiation is no longer a strictly pure thermal spectrum. It is related to the change in Bekenstein-Hawking(B-H) entropy corresponding to black hole event horizon and the cosmological horizon. It is shown that the result satisfies the unitary principle. We also derive the correction term of B-H entropy. It leads to a new understanding of thermal radiation of the black hole.