The transient electromagnetic detection technology and equipment for boreholes in coal mines is the first international set of electromagnetic methods and equipment to detect hidden water hazards around underground coal mines precisely. It enables long-distance directional borehole transient electromagnetic detection with a detection range of up to 30 meters radially and nearly 1000 meters in depth. It meets the requirements for long-distance and long-duration detection during rapid tunnel excavation. It can also be used for hydraulic fracturing, grouting effectiveness assessment on the floor, and detection of other radial targets/anomalies in boreholes. This technology and equipment have played an important role in geological hazard detection in coal mines, such as Xiaohuigou Coal Mine in Shanxi, Luotuoshan Coal Mine in Wuhai Energy, and disaster rescue in Fengyuan Coal Mine in Xinjiang.