Abstract: For the case that section coal pillar width reach 30m in second panel of Tingnan coal mine, physical similar simulation experiment is applied to compare the difference of overburden strata migration when experimental area apply large pillar or narrow pillar. Simulation results show that if section coal pillar is large, the coal pillar will have a strong ability to support, the strata will behave violently, the height of fractured water-conducting zone will be higher and water-conducting fracture will be not easy to close. When coal pillar is narrow, it crushes immediately after the face pushed through a certain distance and integral subsidence of overlying strata also occur. The water-conducting fracture which has already formed easily closed. It helps regenerate aquifuge and will block the fractured water-conducting zone continue to grow. The height of fractured water-conducting zone will decrease too. It also effectively reduces the supporting pressure of coal pillar and slows down the threat of rock burst. By the supporting of section coal pillar, overlying strata appear distortion. Untill the narrow pillar crush will it weaken. This can reduce cracks expansion and damage of the overlying strata effectively.