Abstract: Working face might suffer from water and mud inrush during excavation of a water-rich tunnel, which poses a great threat to construction safety. By physical modeling of the water-bearing structure in front of the working face, the transient electromagnetic response law is summarized. The test and practice show that the positions of abnormal bodies at different distances can be captured accurately by using multi-turn small-coil transient electromagnetic method; by using the multi-directional and multi-angle three-dimensional transient electromagnetic data acquisition technique, the results will be displayed in three-dimensional way, which overcomes the shortcomings of the traditional transient electromagnetic detection that the spatial scope of abnormal body can′t be displayed and effectively improves the visualization and intuition of results interpretation.