The research on exploring advanced electrocatalysts that coupled with structural coherence and fast mass/electron transport characteristics, and maximized electrocatalytic redox activity is extremely urgent for the oxygen evolution reaction (OER), a key process for water dissociation, but it still challenging. Herein, we demonstrate a templated-engaged strategy for the fabrication of highly open and defect-rich Mn-doped Cu(OH)2 hexagonal nanorings (denoted as Mn-doped Cu(OH)2 HNs) by employing Mn(OH)2 hexagonal nanoplates as a sacrificial template. As a result of the successful doping of Mn into Cu(OH)2, the as-prepared Mn-doped Cu(OH)2 HNs possess rich defects and a modified electronic structure, which contribute to the exceptional property as a catalyst for OER electrocatalysis. More importantly, by coupling nickel foam (NF) supported Mn-doped Cu(OH)2 HNs as the anode electrode, NFs supported Pt/C as cathode electrode, a potential of only 1.62 V is needed to drive the water electrolysis to reach the current density of 10 mA cm-2, comparable to the commercial IrO2//Pt/C couple.