The invention discloses a mine transient-electromagnetism three-component detection method. According to geological characteristics of a coal mine, the excitation mode and the receive mode of transient electromagnetism can be adjusted, different diction modes lead to great difference in the number of magnetic field lines cut by a low-resistance object, and secondary fields are different in strength. Three groups of receiving coils are adopted and are placed in three mutually vertical directions, one group of the receiving coils and a transmitting coil are arranged according to a coincide loop, and response data of all directions are emitted and received in one step; in the head-on position of an underground roadway, sector scanning can be realized by changing angles of emitting and receiving coils to acquire more abundant electromagnetic responses, and rich water-bearing areas of the stratum can be further accurately judged.