Abstract: The geophysical characteristics of the coal-bearing strata of the Datong Jurassic coalfield are introduced,the propagation characteristics of the electromagnetic wave in the coal seams are discussed,and the characteristics of the electromagnetic wave penetration of the small structures in the coal seams are described.It is indicated that the underground radio penetration used in the Datong Jurassic coalfield can detects effectively various small structures in the coal seams and guides better thd fully-mechanized mining.