Water oxidation reaction is the bottleneck process of water splitting. The exploration of efficient water oxidation catalysts (WOCs) is of great importance for accelerating this reaction. Herein, a cobalt(II)-containing complex {K2[CoO3PCH2N(CH2CO2)2]}6 (K121) with symmetrical hexameric ring structure and polynuclearity as an efficient visible light-driven WOC is reported. Using [Ru(bpy)3](ClO4)2 as photosensitizer and Na2S2O8 as sacrificial electron acceptor, an optimal oxygen yield of 62.6%, turnover number (TON) of 4350 and turnover frequency (TOF) of 162.6 s−1 are obtained. To the best of our knowledge, this TON and TOF are the highest value among all the catalyst for light driven water oxidation. In addition, a high quantum yield of 60.6% is achieved. Investigation including UV–vis absorption, infrared (IR) spectroscopy, X-ray photoelectron spectroscopy and other techniques confirm that 1 is a stable and efficient catalyst for visible light-driven water oxidation. Collective experiments demonstrate that 1 catalyses visible light-driven water oxidation via water nucleophilic attack (WNA) process and its high activity may be originated from the multiple sites water oxidation catalysis.