The fracturing and caving process of key strata in overburden strata and the distribution law of abutment stress over key strata and immediate roof are investigated and the effect of the rupture of key strata on abutment stress in coal rib and the subsidence of earth’s surface are also analyzed. The simulated results show that the abutment stress over key strata and immediate roof are not uniformly distributed. The rupture of key strata has a great impact on the abutment stress in coal rib, i.e., the abutment stress is much high before the rupture of key strata and reaches to the maximum on fracturing and then decreases sharply after fracturing and the peak abutment stress moves away from working face into coal seam. In addition, the rupture of key strata has also impact on the subsidence of the earth’s surface. The subsidence ratio is basically stable before fracturing and increases remarkably after fracturing and gradually becomes stable as mining.