A visible light-active photoelectrocatalyst, ZnFe-layered double oxide (LDO)/cobalt(II,III) oxide (Co3O4) composites were obtained by calcining the Co loaded ZnFe-layered double hydroxide (LDH) prepared by a hydrothermal and microwave hydrothermal method. The morphological studies revealed that the ZnFe-LDO/Co3O4 composites exhibited a flower-like structure comprising Co3O4 nanowires and ZnFe-LDO nanosheets. Further, when the mass ratio of Co(NO3)2·6H2O/LDH was 1:1.8 and the calcination temperature was 550 oC, the ZnFe-LDO/Co3O4 composite exhibited 93.3% degradation efficiency for methylene blue (MB) at the applied voltage of 1.0 V under visible light after 3 h. Furthermore, the Mott-Schottky model experiments showed that the formation of a p-n heterojunction between ZnFe-LDO and Co3O4 could effectively inhibit the recombination of electrons and holes in the photoelectrocatalytic process. Meanwhile, free radical scavenging experiments showed that the active radicals of •OH played an important role in the degradation of MB. Therefore, the photoelectrocatalytic effect of ZnFe-LDO/Co3O4 provides a simple and effective strategy for the removal of organic pollutants.