To cater for the development of clean hydrogen energy, an efficient oxygen evolution reaction catalyst is urgently needed to increase the efficiency of water splitting. A novel three-dimensional (3D) ternary transition metal hydroxide, FeCoNi-layered double hydroxide (FeCoNi-LDH) nanocage has been successfully synthesized by the cation exchange reaction using the metal-organic framework as a template. The obtained ternary FeCoNi-LDH nanocage displays excellent electrocatalytic activity, such as the low overpotential of 299 mV at j = 10 mA cm(-2) in 1.0 M KOH electrolyte with a Tafel slope of 50 mV dec(-1). Moreover, the FeCoNi-LDH nanocage could also be used as a high-performance electrode for supercapacitor, which presents a high specific capacity of 980 F g(-1) at 1 A g(-1) in 3.0 M KOH. More importantly, the electrode possesses a superb rate capability with 93% capacity retention even at a current density of 20 A g(-1). These results manifest that FeCoNi-LDH has a wide prospect in the application in the energy conversion and storage fields.