Abstract：Three-dimensional forward modeling in latitudinal frequency domain electromagnetic sounding is conducted by using volume integral equation and dyadic Green's function theory,and the accuracy is checked up carefully.The influence of three-dimensional abnormal body upon both the response and the pseudosection of apparent resistivity in frequency-domain electromagnetic sounding depends on conductivity difference between the abnormal body and country rock.The center of measuring electrode is taken as recording point so as to cause both the apparent resistivity over a three-dimensional abnormal body to be maximum and the pseudosection to correspond with the abnormal body quite well.
