Abstract: Due to the influence of early limestone mining ，the surface of MaKeng Iron Mine partially collapsed between Line 83 and Line 87. In order to ensure the safety of underground mining，the micro⁃ tremor method was used to detect the degree of rock fragmentation in the surface subsiding area and the sur⁃ rounding area of 50 m. Carry out microtremor survey parallel to the existing geological exploration line，and delineate the roof，floor and boundary range of the goaf. Roughly identify the plane distribution range and spatial distribution characteristics of the goaf in the area where the collapse is located.The detection results show that the estimated shear wave velocity of limestone strata is 350 ~ 750m/s，which is seriously lower than the conventional value，indicating that the whole limestone rock mass in this area is broken，so safety management should be strengthened before the next exploration work. At the same time，there are many gravel soils in the exploration area，poor grounding conditions for testing，poor data quality and low credi⁃ bility of local areas. Microtremor method can quickly reflect the spatial distribution characteristics of goaf， such as shape，size，buried depth，etc.，and provide a basis for defining the boundary of goaf. It can make a simple evaluation of goaf in the region.

Key words: subsidence area, goaf, microtremor method