Abstract: In southwest China, there is a large range of carbonatite areas. With the construction of city infrastruc? ture, especially rail transit, geological disasters related to karst emerge one after another, and it ′ s critical to understand the law of karst development. As for this issue the geological analysis and geophysical prospecting are the common methods to be adopted. In view of superposition issue of physical property parameters of rock mass in geophysical prospecting, inversive identification of lithofacies was conducted based on maximum posteriori probability under the framework of Bayesian and the Markov property of the strata. Taking the Nanning rail transit line 2 as an example, interpretation and verification of karstcave and grike were carried out on the basis of karst development conditions and documents of drilling holes. The results show that: influenced by horizontal circulation zone of groundwater and fracture structure, the spatial distribution of karst caves and grike goes horizontally; grike often occurs in the marl 10 meters away beyond the station floor, and attention should be paid during construction due to the large size and good connectivity of the karst caves.