In order to explain action range and mechanism of coal-gun phenomenon,numerical simulation research was maken for deforming and destroyed process and acoustic emission phenomenon of surrounding rock in drifting process of a coal mine by use of RFPA2D numerical calculation software.The simulation result showed that coal-gun phenomenon takes place in range of 15 m away from two sides of tunnel and 10 m away from roof in extraction tunnels of mine working face,and the phenomenon is a releasing process of huge amounts of elastic energy accumulated in process of deformation and destroy of tunnel,and it is only a dynamical phenomenon with relatively small energy,not portent information of rock burst.