The invention relates to a device for positioning and detecting an accident well on the basis of a transient electromagnetic method. The device comprises a relief well and the accident well, an emitting electrode and a micro inertial measurement unit combination are arranged on a drill collar in the relief well at an interval, the micro inertial measurement unit combination comprises a three-axis flux-gate sensor, a gravity accelerometer and an underground receiving unit, the emitting electrode is connected with a high-power pulse generation circuit through a cable, the micro inertial measurement unit combination is sequentially connected with a ground receiving unit and a high-power power supply through cables, the high-power power supply can provide power for the high-power pulse generation circuit and the ground receiving unit, the emitting electrode receives current signals and generates a primary field, the primary field motivates an accident well sleeve to generate a secondary field, and signals received by the three-axis flux-gate sensor and the gravity accelerometer are transmitted to and processed in the underground receiving unit and are uploaded to the ground receiving unit. The device can be widely used in the processes of rescuing and detecting in the accident well, grade assessing of an accident and formulating of rescue schemes.