Abstract: In order to accurately detect the concealed goaf left after coal mining, to avoid serious harm to adjacent houses, roads, bridges, railways, etc., in the subsequent mining process, taking Yuanbaoshan Open-Pit Coal Mine as an example, the UAV aerial survey technology is used to accurately obtain the three-dimensional model of the mine surface landform and slope, and the comprehensive geophysical exploration method combining TEM and CSAMT is used to detect the distribution of concealed goaf and water accumulation in the open-pit coal mine in detail. Borehole detection method is used to verify the range of goaf obtained by comprehensive geophysical exploration results. The floor elevation of goaf in borehole position is +284 m, the maximum mining height of coal seam is 6 m, and the roof elevation of coal seam is about +290 m, and the results are highly consistent. The instantaneous water level elevation of goaf in exploration area A is about +371 m. The development height of the water-conducting fissure zone above the goaf is about 44 m, in addition, the instantaneous water level elevation of goaf in exploration area B is about +371 m, the development height of the water-conducting fissure zone above the goaf is about 65 m, and the height of the fall zone is about 26 m. The research results show that by using the transient electromagnetic method and the controlled source audio magnetotellurism method, combined with the drilling and peephole detection method. The accurate detection of concealed goaf in coal mine can be achieved by mastering the basic parameters such as the range of water accumulation in the goaf, the height of the fall zone and the development height of the water-conducting fissure zone, and verifying each other with the exploration results of geophysical exploration and drilling. It provides safe exploration experience for mining layout of open-pit coal mine and is worth popularizing and applying.