Coal mining can cause the strata distortion and surface subsidence. With infrastructure construction scale in our country enlargement, the case of approaching excavation caused by coal mining is increasing and more complicated. The calculation method of current regulations is too simple and don't conform to the present coal mining technology, so it will cause serious waste of resources. By using numerical simulation, this paper regards the influence of coal mining on the above tunnel as approaching excavation problem and studies the tunnel deformation law with three different coal mining mode. Based on the analysis and calculation, this paper proposes measures to ensure that the coal seam mining and tunnel's safety. The result indicates the more smaller the dip angle of coal block the more larger the displacement and the deformation range of tunnel. The most effective method for decrease deformation is the backfill method. If the conditions are permitted, backfill method is the preferred method and longwall caving method is last.