It is important and necessary to know the distribution of tectonic stress field during coal mining. Based on finite element method, the tectonic stress field of Luling mine has been studied. It is showed that the direction of the major principal stress at controlling faults is vertically intersected with the fault strike, and the incremental displacement gets its maximal value at controlling faults. The fold zone can evolve and become to fault by the major principal stress, and the displacement become large when that happened. The volume strain at faults gets its maximal value, and the shear strength of rock become low at the palace of faults. Due to the shear failure of fault, the incremental of shear strain become large near fault, and fault with disturbed belt maybe happened vertically intersected with the strike fault. The results of simulation could guide the coal mining in Luling coal mine.