oft-com:office:smarttags" />///Mentougou County was the main coal-producing area in Beijing area. On the basis of the pre-survey of the slum improvement project of Mentougou County, the paper carefully analyzed the deformation characteristics and geophysical characteristics of a coal-mined cavity in a small pit. The application of the different geophysical methods in the investigation area was discussed, which could help the future mined cavity exploration.oft-com:office:office" />