Abstract: Choosing the overlying extra-thick, hard and no bedding magmatic rock in Jining mine as the research object, through field investigation, rock mechanics experiments, physical similar simulation experiments, the laws of migration and rupture of overlying extra-thick magmatic rock under mining are studied. Results show that the shape of first rupture of magmatic rock is arch; the shape of periodic rupture is similar parallelogram; part of broken block can not form hinged structure and occurs immediately instability; it can't form bond-beam structure; fulcrum balance structure formed by broken blocks's hinge joint on the goaf has little effect to the stope, which can control land subsidence effectively.