Abstract: Taking into consideration the radiation particle reaction with the total energy of spacetime conservation, Hawking radiation from black hole is re-investigated using the Damour-Ruffini method. It is found that the tunneling probability relates to Bekenstein-Hawking entropy, and the radiation spectrum is not exactly thermal. The result is consistent with the works of other researchers， and satisfies the unitary theory of quantum mechanics.

Keywords: 
• Damour-Ruffini method /
• Hawking radiation /
• energy conservation