Abstract: In the detection of deep high-pressure water hazard of coal mine,down-hole electromagnetic method plays a unique role.The article introduces working principles and construction methods of the down-hole DC elec-trical method,down-hole high-density resistivity method,electric transmission tomography and down-hole tran-sient electromagnetic method,as well as their effects of water hazard detection respectively on roof,floor,lateral wall,mining face and pilot detection in blind roadway.The results indicate that the mine electromagnetic method is sensitive to water-bearing low-resistivity body and of relatively high resolution capacity on water-conducting and bearing body in case of a close contact with the target layer of detection or geological body;therefore,it is an effi-cient method for detecting water gushing hazard at coal face.