With the analytical expression of the potential of a point-level power supply with a horizontal layered uniform medium at an arbitrary depth,we take the three-layer electrical structure of the Jiangning seismic station as an example,analyze the variation of the influence coefficient of each layer with depth and pole distance when the symmetrical quadrupole resistivity is observed,and combined with the depth of detection,explore the distributions of influence coefficients with the spacing and depth of electrodes when the Schlumberger arrays are used in the resistivity observation. The results show that the deep-well observation of the Jiangning seismic station has good inhibition to surface and shallow interference. The short-range observation has a significantly better ability to suppress shallow surface disturbance than the long-range observation. Disturbances from surface might be amplified when the deep-well observation is within 100m for the K-type electrical structure. For the fixed sensitivity coefficient,the electrode burial depth increases with the current electrode length. The annual variation features are analyzed by calculating the influence coefficient of each layer. It is reasonable to take 100~150m from the electrode length and 250m from the electrode buried depth. The calculated results could be used as reference for the selection of electrode buried depth and current electrode length when deep-well observation would be used in similar stations.