The survey area is located 18km southwest of Zhangqiu City, 36km west of Jinan, and the terrain is high in the south and low in the north. The strata in the survey area are mainly Ordovician, Carboniferous, Permian and Quaternary. The Quaternary system is mainly composed of soil, with resistivity of 50-100 ohmmeters, which is reflected by medium and low resistivity; The Permian formation resistivity is 100-200 ohmmeters, which is reflected by medium resistance; The resistivity of Carboniferous limestone is 200-300 ohmmeters, which is reflected by medium and high resistivity. The resistivity of Ordovician limestone formation is 600-800 ohmmeters, which is the highest electrical property in the area. Most of the mined-out areas in the survey area are water-filled. The resistivity of the water-filled mined-out areas is 50-100 ohmmeters. The electrical properties of different geological layers, surrounding rocks and mined-out areas in the survey area are significantly different, and the geophysical exploration conditions are available. Two survey lines are arranged for this transient electromagnetic survey (as shown in the figure). The distance between the points of Line 1 and Line 2 is 2 meters. According to the geological data, the depth of the mined-out area of the coal mine in survey lines 1 and 2 is about 90-100m. It can be seen from the transient electromagnetic inversion diagram in Figure 1 that there is a low resistance area between the horizontal distance of 25m-40m and the depth of 80m-95m for Line 1, and the inversion result is good.