An imidazoline corrosion inhibitor, 1-hydroxyethyl-2-lauryl imidazoline sulfuric ester (LIMS) was synthesized by quaternary ammonium reaction with lauric acid and N-hydroxyethyl-ethylenediamine as raw materials and amino sulfonic acid as the quaternarization reagent. Its corrosion inhibition performance and adsorption behavior to A3 steel in 10% hydrochloric acid solution were investigated by means of weight loss, polarization curve, electrochemical impedance spectroscopy (EIS) and environmental scanning electron microscope (ESEM). The results revealed that corrosion inhibition efficiency of up to 93.1% when LIMS at the mass concentration of 0.80g/L. After adding the corrosion inhibitor, anode/ cathode action coefficient fa and fc were lower than 1, both values were similar, LIMS could inhibit cathode and anode reaction simultaneously, was a mixed type inhibitor. The research also indicated that the adsorption of the inhibitor on A3 steel was in agreement with Langmuir adsorption isotherm and the inhibitor molecule was adsorbed into A3 steel surface spontaneously. In addition, chemisorption was the predominant mode of adsorption. The inhibition efficiency of LIMS was up to 90.6%, superior to that of urotropine（78.5%）, benzotrizaole（82.9%）, PS-1（84.2%）and IS2129（87.3%）under the same condition．