HVDC grounding electrode line is different from normal DC transmission line. Normally, the average of voltage and current are small, beside the address electrode resistor is small, so that make the DC grounding electrode lines fault location difficult. Many simulations show when grounding electrode line is fault and the ground resistance is greater than or equal to the address electrode resistor, then little current flows into fault point. The fault point voltage is not the minimum for the distribution of voltage along the line but the address electrode voltage. So the fault location algorithm based on the equal of fault point voltage has greater error. A new fault location method which can withstand high impedance based on voltage equal at pole point is presented. Many simulations show that the algorithm can accurate position the electrode line.