In this paper a 3D FEM model is established to simulate the dayuliang tunnel which is located in the gob area. The vertical and horizontal surface displacements of gob area are obtained in different simulation condition. By these calculated results the character and key region of gob surface subsidence is analyzed. The warning line of subsidence basin is determined. In order to control tunnel structural’s stability its deformation and stress character are also researched to determine stress concentration and important supporting position. These analysis results provide a scientific basis and technical guidance for the tunnel construction in gob area.