Water splitting has been considered as one of the most promising strategies for renewable energy production. The process of water electrolysis is greatly influenced by the sluggish kinetics of the oxygen evolution reaction (OER). Therefore, it is necessary to develop a very effective catalyst for improving OER performances. The electronic properties and morphological structure of electrocatalysts can significantly affect their OER performance. Electrocatalysts with the morphology of dendrite can expose more active sites which would enhance the OER activity. Here, the 3D dendritic Ni@Ni(Fe)OOH core-shell material has been developed on nickel foam (NF) with a controllable morphology and composition using an extremely simple and fast method. The doping of Fe can effectively modulate the morphology and the electronic structure of Ni@NiO to improve the intrinsic activity of active sites. The porous dendritic core-shell structure could allow more active sites to grow and transport electrolyte faster. At the same time, the internal Ni core can work as fast electronic transfer networks. As a result, the optimized Ni@Ni(Fe)OOH/NF shows a great catalytic performance for OER with an overpotential of 226 mV cm(-2) at 10 mA cm(-2) and an excellent stability in alkaline solution. The results given in paper may bring important implications for the development of a series of hydrogen and oxygen catalysts.