Old goaf water became the key object of prevention and control of coal mine water disaster accidents because of its hidden water accumulation. In order to realize the accurate exploration of the water accumulation in the old goaf of coal mine, this paper took No.15150 Face of Xin 'an Mine as an example, and used the borehole transient electromagnetic technology to detect the development of the water-conducting fracture zone in the upper 90 m of the upper roadway of the working face and the influence range of the old goaf water. By analyzing the cross section and three-dimensional diagram of the apparent resistivity change, it was found that there was a strong abnormal area and a weak abnormal area in the roof, and the suspected surrounding rock cracks in the strong abnormal area were relatively developed and caused by water. Combined with the field verification, it was judged that the detection area was not affected by the destruction area of the old goaf, and the pre-exploration and prevention of mine water damage were realized.