Abstract: This paper deals with the characteristics of the influence coefficient in the cases of array deeply buried for geoelectrical resisitivity observations, which has been developed in recent years and aimed at decreasing or even eliminating the interference from the top layer and exacting the possible earthquake-related information from depth. The horizontal layered model has been taken into consideration in the study and the algorithm of the boundary integral equation has been adopted for calculating the influence coefficient, when the configuration of the array is located in the different depths under the ground surface. The calculations demonstrate the features that influence coefficient has been closely controlled by the structure parameters of the model, the depth of the buried array and the separation of the array. The results in this paper strongly suggested that one must pay great attention to the following steps in the studies of the deeply-buried array: the first, exploring finely the structure parameters of true resistivity in the observed media, and the second, confirming the depth for the array having been located and the configuration parameters corresponding to the model structure.