In order to correctly and objectively evaluate the floods existing in coal mining, find out the source of floods and the degree of influence by floods, the hydrogeological conditions of Canghai Coal Mine were investigated. And the hydrogeological conditions within the mine field were found out, including thickness, lithology and water content of each aquifer and aquifuge. Through the analysis of mine water filling factors, water filling characteristics, hydraulic connection between water-bearing strata, and the study of groundwater recharge, runoff and discharge conditions in the mining area, the water inflow of the mine in the future was predicted. In order to analyze the degree of water disaster in coal mines, the transient electromagnetic geophysical prospecting technology was used to find out the karst development characteristics and water abundance of the overlying strata of the coal seam. The water filling and distribution characteristics of No.6 and No.8 coal seams were obtained and interpreted, and the water abundance abnormal area was delineated. The research results could provide water prevention and control countermeasures for the mine, and guide the coal mining area, roadway layout and advanced water exploration and drainage work.