Electrocatalysts can reduce the reaction energy barrier, make water splitting and hydrogen production more effective, and the catalytic efficiency, preparation cost and large-scale use of electrocatalyst still face challenges. This paper introduces an inexpensive, high-precision, high-performance OER electrocatalyst. The 304 stainless steel mesh is treated in a boiling solution containing 2mol/L nickel source for 120s to obtain self-supporting electrocatalyst (denoted SS-Ni-OH2M-120s) with excellent OER performance. This self-supporting electrocatalyst facilitates industrialization and scale production. The overpotential of SS-Ni-OH2M-120s electrocatalyst obtained at the current density of 10 mA cm-2 was 214 mV, which was about 127 mV lower than that of the blank 304 stainless steel mesh. After the constant potential polarization for 10 h at a current density of 20 mA cm-2, the catalytic performance displayed no obvious change, indicating excellent stability. When SS-Ni-OH2M-120s anode combined with the Pt mesh cathode (SS-Ni-OH2M-120s//Pt mesh) for overall water splitting, a decomposition voltage of 1.61V at the current density of 10 mA cm-2 was achieved, which is 0.23 V lower than the commercial IrO2/SS//Pt mesh.