In order to clarify the influence of deep faults on coal seam mining, a series of simulation tests on the width of coal pillars of F1 fault of boundary faults in a mining area of Yangquan Coal Mine were carried out by means of similar simulation tests, and the deformation and failure characteristics of rock mass in fault zone, stress and displacement changes of coal seam floor were monitored. The test proved that with the increase of mining distance, the deformation and cracking of the fault would occur; the closer to the fault, the more violent the stress change of the coal seam floor; the narrower the width of the coal pillar of the fault, the more obvious the displacement of the rock mass in the fault zone, and the trend of activation. Therefore, based on similar test data and empirical formula, it was deduced that the width of waterproof coal pillar should be set at 50 m or more for F1 boundary fault. Only in this way can the displacement difference of rock mass in deep fault zone be avoided and the safety of coal seam mining production be ensured.