Moringa oleifera leaves are widely used because they are rich in resources and contain a variety of functional components. This study focuses on the Moringa oleifera leaf extract (MOLE) obtained by ultrasonic extraction method as an efficient green corrosion inhibitor for CRS in 0.10 mol/L NH2SO3H. The corrosion inhibition properties and mechanism of MOLE were evaluated by weight loss method, electrochemical method and surface analysis. The results show that MOLE has good corrosion inhibition performance on cold-rolled steel in NH2SO3H medium. And the corrosion inhibition rate increased with the increase of MOLE concentration. Furthermore, the corrosion inhibition rate is 91.63% with 0.10 g/L MOLE at 30 °C. The adsorption of MOLE on the surface of cold-rolled steel follows the Langmuir adsorption isothermal formula, and which has the effect of corrosion inhibition through mixed adsorption. Both the corrosion and corrosion inhibition processes are controlled by charge transfer. The addition of MOLE can significantly increase the resistance value of charge transfer, and a dense adsorption film is formed on the surface of CRS, by which the corrosion of CRS by H+ and \( {\mathrm{NH}}_2{\mathrm{SO}}_3^{-} \) is effectively prevented, thus achieving better corrosion inhibition performance. The results of XPS, AFM and contact Angle confirm the existence of effective functional groups in MOLE, which reduces the surface roughness and increases the hydrophobicity of CRS.