Integration of water oxidation catalysts on conductive support without polymer binder is an appealing strategy to improve the catalytic activity for electrochemical oxygen evolution reaction. Herein, the hierarchical CuO dandelion-like materials assembled from numerous ultrathin nanosheets are directly grown on Cu foil to produce a 3D oxygen evolution anode (CuO NSDs/CF). As a result of its integrated configuration and high electrocatalytic active sites, the anode exhibits superior electrocatalytic water oxidation activity in 1.0 M NaOH solution, associated with a small overpotential of 370 mV at 10 mA cm−2 and a low Tafel slope of 41 mV dec−1. Furthermore, the anode can maintain a relatively stable current density at 1.65 V versus RHE for at least 24 h, and a high Faradaic efficiency of 98% is also achieved.