Abstract: CoFe bimetallic hydroxides (CoFe BMHs) find wide applications as excellent catalysts in the field of water splitting. However, no study has systematically investigated the influence of the morphologies of CoFe BMHs on catalyst performance. In this study, CoFe BMH nanoflowers (CoFe BMH NFs), CoFe BMH nanosheets (CoFe BMH NSHs), CoFe BMH nanorods (CoFe BMH NRs), and CoFe BMH nanospheres (CoFe BMH NSPs) were prepared on nickel foam via a hydrothermal method. CoFe BMH NSHs exhibited the most beneficial catalytic activity. At a current density of 100 mA·cm⁻², its overpotential for oxygen evolution reaction (OER) was 282 mV, and the overall water splitting voltage was 2.05 V. The double-layer charging capacitance (C_dl) value of CoFe BMH NSHs was the largest in CoFe BMHs, which proves that CoFe BMH NSHs have the largest active area. Furthermore, the active site in the OER process was metal oxyhydroxide (MOOH) through in situ Raman characterization, and the generation of the active substance was an irreversible process. This work provides important insights into the design of catalyst morphologies and offers valuable guidelines for the enhancement of the performance of other catalysts.