Abstract: In order to analyze the development law of overlying strata fracture zone in filling mining, the fracture mechanics process of key strata in filling mining was analyzed by using the theory of plate and shell. It is found that the water-conducting fault zone develops layer by layer with the increase of mining thickness, rather than progressive development with the increase of mining thickness. The numerical simulation method is used to reproduce the development law of overlying rock fracture zone at different filling heights after mining. It is concluded that the development of overlying rock “two zones” has a critical effect with the change of equivalent mining height, that is, the quantitative change of filling height will cause the qualitative change of the deformation and failure height of overlying rock. The development of overlying strata fracture zone after mining in filling working face is observed. The measured results are in agreement with the theoretical analysis results. The measured results verify the conclusions of the theoretical analysis and numerical simulation.