Abstract: The submarine cable is an important component of offshore wind power system and the grounding circulation is a key factor to restrict the designing and operating of the submarine cable. Practical operating experiences show that there is a serious imbalance of the grounding currents in the onshore and offshore sections in the offshore wind field, but the cause of this mismatching is unknown, let alone a clear judgment on the operating state of the offshore cables with this phenomenon. In this paper, based on the actual structure of the submarine cable, we establish a distribution parameter model. For both the armor grounding and the armor/sheath grounding, the submarine cable grounding circulating currents are analyzed. The reason for the extremely mismatching grounding circulating current of the armor grounding cable is the existence of a short circuit resistance between the armor and the sheath of the offshore section; the reason for the extremely mismatching grounding circulating current of the armor/sheath grounding cable is the existence of a short circuit resistance between the armor and sheath or mismatched grounding resistance at both the ends of the cable. On this basis, an evaluation system of the submarine cable operating condition based on the circulation is proposed, which may provide a reference for the judgment of the actual submarine cable operating condition.