2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/36477The classical first law of thermodynamic for Kerr-Newmann black hole (KNBH) is generalized to that in quantum form on event horizon. Then four quantum conservation laws on the KNBH equilibrium radiation process are derived, and Bekenstein-Hawking's relation S=A/4 is recovered. It can be argued that the classical entropy of black hole arise from the quantum entropy of field quanta or quasi-particles inside the hole.10 Pages, in Latex, no figureGeneral Relativity and Quantum Cosmologytext