To achieve extremely effective photoelectrochemical (PEC) water splitting, it is imperative to suppress charge recombination at the interfaces between the oxygen evolution cocatalyst (OEC) and BiVO4. In view of this, a robust interfacial interaction between BiVO4 and MnFe-MOF was successfully established, and the optimized BiVO4/MnFe-MOF Photoanode exhibits a photocurrent density of 3.64 mA cm-2 at 1.23 V versus the reversible hydrogen electrode (RHE) under AM 1.5 G illumination (100 mW cm-2). Owing to the robust metal-support interaction (SMSI) between BiVO4 and MnFe-MOF, the electron transfer from Bi/V to MnFe-MOF, leading to the formation of the Bi/V-O-Mn/Fe chemical bonds and electron-rich Fe species (Fe2+), which readily provides an extra driving force for the extraction of the photogenerated holes from BiVO4 to the MnFe-MOF. Furthermore, the introduction of Mn atoms regulates the electronic structure of Fe sites in MnFe-MOF, thus accelerating the kinetics of surface water oxidation. This work sheds light on the function of the interface and active site electronic structure modulation of photoelectrodes for sustainable solar energy conversion.