The corrosion inhibition performance of the cationic surfactant dodecyl dimethyl lbenzyl ammonium chloride (1227) on cold rolled steel in 0.10 mol/L Cl₃CCOOH trichloroacetic acid solution was investigated by mass loss measurement, electrochemical test, scanning electron microscopy (SEM), atomic force microscopy (AFM) and contact angle tester. The results show that 1227 can effectively suppress the corrosion of cold rolled steel in 0.10 mol/L Cl₃CCOOH solution. The inhibition efficiency of 40 mg/L 1227 is as high as 97.4% at 20^oC. The higher the corrosion inhibitor concentration, the higher the corrosion inhibition efficiency, and the higher the temperature, the lower the corrosion inhibition efficiency. The adsorption of 1227 on CRS surface follows Langmuir adsorption isotherm, and the type of adsorption is a mixture of physical and chemical adsorption while chemisorption as the main effect. The potentiodynamic polarization curve shows that 1227 can simultaneously inhibit both the cathodic- and anodic-reactions, and so 1227 is a mixed inhibitor and its action mechanism is "geometric covering effect". In the Nyquist diagram, along with the increase of 1227 concentration, the capacitance arc and the charge transfer resistance all increase, therewith, the inhibition effect increases. The result of SEM and AFM analysis proves also that 1227 can effectively retard the corrosion of the steel in Cl₃CCOOH solution. The contact angle results show that the addition of 1227 enhances the hydrophobicity of CRS surface.