Strategy of anchoring alloy nanoparticles made up of the efficient catalytic element (e.g., Ni, Fe) on dodecyl sulfate (DS^-)-intercalated NiFe layered double hydroxides (DS^--NiFe LDH) obtained by a convenient one-step hydrothermal coprecipitation method for essentially enhancing oxygen evolution reaction (OER) performance was proposed. The results of structural characterization indicate Pt₂FeNi alloy nanoparticles evenly distribute on the surface of DS^--NiFe LDH. The sizes of the Pt₂FeNi nanoparticles, closely related to their OER performance, could be well-controlled by adjusting the amount of H₂PtCl₆ addition. The composite structure of as-prepared product was stable during processes of synthesis, exfoliation, self-assembly, and subsequent electrocatalytic OER. Rigorous electrochemical test proving the contributing catalytic active sites was located at the interface between Pt₂FeNi and DS^--NiFe LDH, and the Ni and Fe were the major active elements while O atoms are adsorption sites. The formation of Pt₂FeNi nanoparticles could greatly prompt the reduction of Tafel slope. The best-performing Pt₂FeNi/DS^--NiFe LDH with a Pt content of 0.98 wt% achieved low overpotential of 204 mV at 10 mA cm⁻² and 262 mV at 50 mA cm⁻². This work provides a convenient and effective strategy to create additional active sites for enhancing OER performance of NiFe LDH and make contribution to its wide application.