Abstract: The grounding resistance must be reasonably calculated and reduced in order to improve the observation accuracy and quality, enhance the immunity of electromagnetic coupling when using electrical measurement. It can be reckoned according to the current field property and the conductor resistance definition. Through using MATLAB software, this paper simulates and analyzes the grounding resistance changes with the electrode radius, the buried depth and the covered distance by the soil from the rod electrode surface so as to determine its main size. Since the electrode size is generally relatively fixed, the methods of reducing the grounding resistance are mainly through reducing soil resistivity near the electrode and paralleling the grounding electrodes. Through the simulation analysis of the grounding resistance variation with the covered radius of replacement soil and the coefficient of assembling and shielding effect variation with the electrode spacing, we can draw the conclusion that the covered radius of replacement soil is taken within the range of 100~150 cm and the electrode spacing is twice greater than that of the buried depth. Now the grounding effect is the best.