Underground coal mining brings many environmental problems, which are mainly caused by mining-induced fractures. Hence, obtaining a better understanding of fissure is necessary to solve the issues. This study first uses a software (PFC3D) to simulate the development of the fracture network and then adopts transient electromagnetic method (TEM) in Ganzhuang Coal Mine to investigate the distribution of fractures. The results show that overburden strata are full of cracks, which connect with each other, forming a fracture network. Besides, the shape of fissures in the net is similar to "O". Also, the fractures are periodically created along the strike.