The invention discloses a concrete reinforcing bar corrosion inhibitor with triethanolamine benzoate as the main component. The corrosion inhibitor is specifically prepared from, by weight, 15-50% oftriethanolamine benzoate, 5-15% of phosphate, 5-10% of organic additive and the balance water. In use, the corrosion inhibitor is mixed with cement, sand, stone and other gel materials after being directly added to water to be dissolved and evenly mixed according to the recommended amount of the corrosion inhibitor, meanwhile the water consumption of concrete mixing is deducted according to the ratio of water in the corrosion inhibitor composition, and the addition amount of the corrosion inhibitor is calculated according to the weight of cement required for each cubic meter of concrete building. The reinforcing bar corrosion inhibitor can effectively control or relieve the corrosion to reinforcing bars in concrete, and the corrosion starting time of the reinforcing bars in the concrete isgreatly delayed. The corrosion inhibitor can be widely used for industrial and civil newly-constructed rebar concrete buildings such as coastal buildings, harbor wharfs, bridges and culverts.