Abstract: Due to the limited mining space in underground coal mine, it had a certain influence on the detection of unknown regional geological conditions and hydrogeological conditions in a certain distance in the direction of roadway excavation. Aiming at the problem of roof watering when the return air roadway of No.21301 Face of Donggucheng Coal Industry was excavated to the full scale of 326 m, in order to ensure the safe and smooth excavation of the roadway, the area in front of the excavation head was quickly explored whether it was part of a low-resistance abnormal area, and the transient electromagnetic advanced detection was carried out. The water abundance abnormal area with upward tendency was found within 120 m in front of the roof. After drilling verification, it was determined that the water inflow from the roof of the roadway was the water abundance abnormal area caused by the fault fracture zone. After drainage, the return air roadway passed the small fault safely, which ensured the production safety of the mine and provided data for mine water prevention and control.