Abstract: large numbers of the buried faults are exist in the coal mines in China,which very great difficulty to the construction's design of coal mine and to the safety of coal mine's production.This text introduces the work principle of the method of controlled source audio-frequency magnetotellurics (CSAMT),analies the effect of this method in detecting buried fault in coal mine,And the means of field exploration in a coal mine in Shanxi solves the problems in design and production of coal mines and,proves that the advance forecast of such method in detecting buried fault in coal mine is reliable.The anomaly of buried fault shows that transversal resistively isopleths occurrence miscount break,combine with distortion phenomenon,and have denseness gradient belt obviously.