Improving overall water electrolysis efficiency is challenging due to difficulties in designing high-efficiency, non-noble metal oxygen evolution electrocatalysts. The key to success lies in improving the electrocatalyst's specific surface area and optimizing its electronic structure. In this study, a novel method for obtaining coronal manganese cobalt Prussian blue analogues (MnCo PBA) with high specific surface area was developed through simple chemical etching. The MnSe/CoSe₂ composite, derived from coronal MnCo PBA, retains the high specific area characteristics of the precursor. The resulting coronal MnSe/CoSe₂ demonstrates excellent OER performance, attributed to the high specific area composite MnSe/CoSe₂, which exposes more active sites and promotes synergistic effects between its components. The overpotential at a current density of 10 mA cm⁻² is 360 mV, and the electrocatalyst displays long-term stability of up to 200 hours. This work offers a unique and effective approach to designing high-performance OER electrocatalysts.