Peanut shell extract was prepared by reflux method using forestry and agricultural residue of peanut shell as raw materials. The corrosion inhibition properties of the peanut shell extract (PSE) on cold-rolled steel (CRS) in hydrochloric acid (HCl) solution was studied using mass loss measurement, potentiodynamic polarization curve (PDP) and electrochemical impedance spectroscopy (EIS), metallographic microscopy (MM), and scanning electron microscopy (SEM). Additionally, the relationship between the surface tension and conductivity of the corrosion inhibitor solution and the performance of PSE was also investigated. The results indicate that PSE exhibits excellent inhibition properties for CRS in 1.0 mol/L HCl solution, with the inhibition efficiency (η_w) increasing as the concentration of PSE increases. The inhibition efficiency (η_w) can reach up to 93.15% with the addition of 200 mg/L PSE at 40 ℃. However, the inhibition efficiency decreases with higher acid concentration and with longer inhibition time. The adsorption of PSE on the CRS surface follows the Langmuir monolayer adsorption model, with |ΔG⁰| in the range of 20 kJ/mol to 40 kJ/mol. This indicates that the adsorption of PSE on the CRS surface involves a combination of physical and chemical interactions. PSE acts as a mixed inhibitor, effectively inhibiting both the cathodic hydrogen evolution reaction and the anodic dissolution reaction. The Nyquist diagram features a single capacitive reactance arc, indicating that the corrosion of CRS in an acidic medium is primarily inhibited by charge transfer resistance. The microtopography analysis using MM and SEM confirmed that PSE effectively prevented the corrosion of CRS by HCl. In comparison to the bare surface, the surface hydrophobicity of CRS increased after inhibition test. The conductivity of the solution decreased after inhibition test, and the surface tension decreased with increasing PSE concentration. The surface tension of the solution after inhibition test was higher than that before.