A new method is presented to calculate the non-uniform of current distribution on grounding electrode. Based on the equivalence of low frequency current field and static electric field, the electrode is simplified to he a line charge model with limited length. The charge distribution on the model is calculated by solving equilibrant equations, and the current distribution along the axis of electrode was got. The current density at the end of electrode can he several times of that in the middle, the non-uniformity get worse with the increasing of electrode length and numbers. This is what lead to several problems on grounding systems such as inefficiency, the partial overheat and the severe corrosion of electrode.