The synergistic catalysis of bimetallic catalysts is one of the important ways to improve the catalytic performance; therefore, the development of efficient bimetallic water oxidation catalysts (WOCs) has received extensive attention. This work proposed a bimetallic Fe3O4/CuO catalyst prepared in situ from the Cu-Fe Prussian blue analogues precursor, promoting Fe3O4-modified CuO as a highly efficient and stable bimetallic WOC. The Fe3O4/CuO exhibits superior and robust catalytic activity for the oxidation of water. Compared with the reported results, it has a higher O-2 evolution rate of about 4406 mu mol.h(-1).g(-1) and a maximum value for the yield of O-2 as 83.2%, mainly because of the synergetic effect between Fe3O4 and CuO in the complicated water oxidation reaction (WOR) process. We hope this work will be useful for other researchers to design new transition metal bimetallic catalysts for WOR.