Abstract: In order to probe the significant difference between the surface and deep well georesistivity observations, the electrical structure beneath Jiangning geoelectric station was detected, and a horizontally layered electrical structure model was proposed in this paper. Subsequently, we used the model to calculate the apparent resistivity for each configuration of surface and deep-well observation systems. Comparison of calculated georesistivities, with observed ones shows that the observations of the surface configurations with a long-distance current electrodes and those of deep-well configurations can be reasonably interpreted, that is to say, the difference between the surface and deep-well observations is reasonable, which is resulted from the different electrical structure beneath Jiangning station.