In the light of the electromagnetic coupling effect between the receiving cables and between the receiving cable and the earth in data collection in CSAMT and through electromagnetic coupling theory and equivalent circuit calculation,the authors derived the forward modeling formula. Based on a variety of models and forward simulations in comparison with actual field data,the authors studied three factors affecting electromagnetic coupling effects in CSAMT,i.e., cable length, ground resistance of non-polarized electrode, and signal frequency, and summarized three kinds of phenomena corresponding to electromagnetic coupling characteristics: the longer the cable of receiving system, the larger the electromagnetic coupling effects between the cables, the more obvious the distortion of apparent resistivity curve in the high frequencies, and the more evident the distortion of curves; the bigger the ground resistance of non-polarized electrode, the more obvious the distortion of apparent resistivity curve in the high frequencies, and the more evident the distortion of curves; the greater the signal frequency, the larger the inductance and the capacitance, and the more obvious the distortion of curves. When the signal frequency increases to a certain value, the capacitance and the inductance no longer continue to increase, and the curves tend to be stabilized.