In some areas of Gansu province, the common geophysical methods for groundwater exploration seem to be ineffective in classifying the structures of strata, locating the positions of faults, finding out the shape of bedrock surface and estimating the distribution of groundwater. Using TEM exploration combined with an analysis of borehole data, the authors made some breakthrough in solving the above-mentioned hydrogeological problems. The results prove the effectiveness of this method in ground water exploration.