Due to strong heterogeneity and complexity often existing in mining engineering geological environment, it was hard for the present theory to explain deformation behavior of overlying strata under repeated mining condition in complex thick coal seam. Based on the original coal region geological conditions in eastern of Laohutai coal mine, Fushun Mining Group, using MIDAS & FLAC3D numerical simulation method, studied the deformation and failure law of overlying strata under repeated mining condition in complex thick coal seam. The results showed that under repeated mining condition in complex thick coal seam, the caving zone and fissure zone formed by working face mining, were controlled by fault and rock interfaces. The research results offered help to waterproof and roof maintenance work to Laohutai coal mine and coal mine with similar conditions.