Abstract：First the distribution laws of stress fields in the course of mine tunnel excavation are simulated by means of FLAC3D software，and the stress value in each unit is obtained. Then according to the stress values and the coupling laws between electromagnetic emission(EME) strength and stress fields during the deformation and fracture of coal or rock，the changing laws of EME strength during mine tunnel excavation are studied. The results show that the changing rules of simulated stress are in accordance with that of the theoretical analysis and the practical strata stress，which shows that the FLAC3D method can appropriately simulate the changing law of stress field in the course of mine tunnel excavation. The simulated values by taking a large area as EME resources are only 3～8 percent larger than that by taking the stress concentration zone as EME resources，which show that EME signal received on the stress concentration zone reflects the deformation and fracture degree of coal or rock. The EME signal in head-on area along the direction of tunnel excavation increases constantly to the summit value and then falls down along with the computation time step. The EME strength in the same monitoring point increases gradually with the increasing computation time step. The increase of it slows down when it increase to a certain value. The changing of EME strength reflects the changing of internal stress after excavation. The practical measured results of EME strength have the same changing tendency as the simulated results，which also testify the feasibility of the coupling method between EME strength and stress.
