Abstract: It is a difficult for hydrological geophysics to rapidly and accurately detect the waten channels and small water inrush structures because of the influence of geological and topographical conditions. Through the study of the key technical problems in TEM for hydrogeological exploration in coal mines, the features of sensibility to low resistivity, high horizontal resolution and rapidity of TEM were sufficiently used. New inversion technology was adopted to enhance REM accuracy. Positioning detection of water inrushing structures was rapidly and accurately performed in many rescues during water inrush and flooding in coal mines. The social and economic benefits are obvious.