Using oleic acid and hydroxy ethyl ethylene diamine as raw materials, an imidazoline intermediate is generated through amidation and cyclization reactions, and then ethylene oxide is added to polymerize to obtain an ethoxylated imidazoline rust inhibitor. The corrosion inhibition performance of this rust inhibitor on Q235 carbon steel in 3.5% NaCl saturated Ca(OH) 2 was evaluated by weight loss method, salt water immersion method, salt water immersion drying experiment, electrochemical comprehensive experiment and scanning electron microscope, and through the cement paste fluidity experiment, tested the influence of the rust inhibitor on the concrete fluidity.The research results show that the rust inhibitor can effectively protect Q235 carbon steel from corrosion in 3.5% NaCl saturated Ca(OH)2 corrosive medium. Through electrochemical experiments, it proves that the rust inhibitor is a mixed type rust inhibitor that mainly inhabits the anode reaction. When the mass concentration is 4%, the corrosion inhibition efficiency of the steel bar reaches 99.13%, and the scanning electron microscope shows that the surface of the carbon steel is smooth and flat. The experimental results of cement paste fluidity show that the rust inhibitor has no obvious adverse effect on the fluidity of concrete.