Herein, Moringa leaf extract (MLE) was prepared via an ultrasound-assisted extraction method, and of which the potential chemical functional groups were characterized by means of Fourier transform infrared spectroscopy (FTIR). Next, the corrosion inhibition performance of MLE for cold-rolled steel in 0.5 mol/L H₂SO₄ solution was systematically investigated via weight loss measurements, electrochemical measurements, atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS) etc. The results demonstrate that with a dosage of 100 mg/L MLE, a corrosion inhibition efficiency of 90.06% may be reached for cold-rolled steel in 0.5 mol/L H₂SO₄ solution at 30 ℃. The adsorption of MLE on the surface of cold rolled steel follows Langmuir and Freundlich isothermal models. The calculated standard adsorption Gibbs free energy (∆G⁰) ranges from -26.12 to -31.86 kJ·mol^-1, indicating that the adsorption is mainly a mixed mode of physical and chemical adsorption, and confirmed that MLE has the best adsorption performance at 30 ℃. Electrochemical analysis also confirmed that MLE acts as a mixed-type inhibitor. Its primary mechanism involves increasing the charge transfer resistance at the steel/acid interface, thereby effectively inhibiting the electrochemical corrosion process. The presence of MLE will reduce the surface roughness and hydrophilicity of steel; Furthermore, XPS analysis further revealed that the key mechanism of MLE's corrosion inhibition was the formation of an adsorption film on steel surface, quantum chemical calculations show that the oxygen-containing groups in MLE serve as active adsorption sites. It provided a new idea for the high value utilization of moringa leaves in industrial anticorrosion.