Under the influence of mining activity, because of the development of water-diversion fracture zone the danger of water-inrush may exist in coal-measure strata in roof and floor of which there are water-bearing strata. The physical simulation experiments have been done with the plane models to study the deformation and failure law of overlying stratum in the process of mining coal in a certain coal min. The distribution law of the stress in the overlying stratum and the development law of the stress chaoging with the advance of mining front had been acquired. The results showed that under the simulated condition the fracture zone caused by mining coal seam has touched upper the water-bearing stratum, so it is necessary to take measures to ensure the safety in production during the mining activity.