The grounding performances and technical economy of common ground electrode are different from those of regular ground electrode, of which the comparisons between regular electrodes and common electrodes can help engineers optimizedly design electrodes. According to the major modes of multiple convert stations operating in synchronism, the grounding current, ground resistance, and economy etc are analyzed and compared for regular ground electrode, one common electrode and two common electrodes of multi-stations. It is shown that common electrode is better than regular electrode from both environmental influence and economy aspects, where the electrode site is exigent for one common electrode of multi-stations. If better electrode site is available, one common electrode has smaller electromagnetic influence range of step voltage than that of two common electrodes, of which both are on the same levels in the construction investments.