Abstract: To investigate the form of electromagnetic field stimulated by single electrode in layered ground model this paper gave the expression of the electromagnetic fields in frequency domain in layered earth excited by single electrode, and then those electromagnetic fields are calculated by digital filtering method. The results show that curve pattern for electrical field is simple and indicates the earth structure well; the curve pattern for magnetic field is very complex. The apparent resistivity is defined by electromagnetic fields. On the model of two layers, the resistivity curve approaches to the resistivity of the first layer in the high frequency and at large distance and to the resistivity of the second layer in the low frequency and at large distance.