The inhibition ability of N,N′-bis(4-formylphenol)-1,2-Diaminocyclohexane (4-HCD) on the carbon steel in 1M hydrochloric acid solution was studied by electrochemical techniques and weight loss measurements. 4-HCD inhibited steel corrosion in 1M HCl solution significantly and the inhibition efficiency increased with 4-HCD concentration. The results indicated that after 5h, this inhibitor has a maximum percentage inhibition efficiency of approximately 71% in the presence of 2mM inhibitor. The adsorption of the inhibitor was followed Langmuir adsorption isotherm with the standard adsorption free energy of −25.66kJmol−1. Computational investigations of the studied inhibitor are performed by using HF method with 6-31++G(d,p) and 6-311++G(d,p) basis sets.