Abstract: The use of wellhead electromagnetic wave CT technology can be underground Karst, broken belt and other issues for fine exploration. In this paper, the Karst area model is used to simulate the electromagnetic wave CT of Karst area by numerical simulation method, and the attenuation and response characteristics of electromagnetic wave in Karst development area are discussed. The results show that the method has a good effect on the detection of Karst development area, and the results show that the method is effective in detecting the Karst area.