Abstract: The adverse geologic conditions such as Karst often threaten the safety of subway engineering. It is necessary to ascertain the location and scale of the Karst during the exploration stage. However, the randomness of Karst distribution and the complexity of urban environment make Karst exploration quite difficult. In this paper, we use the Opposing Coils TEM and Elastic Wave CT to prospect the Karst development of a subway project in Nanjing and analyze the application effect of comprehensive geophysical prospecting method which is based on opposing coils TEM and elastic wave CT method in Karst exploration.