A novel and effective water-soluble aldehydes (β-HA) as corrosion inhibitor was synthesized for N80 steel corrosion in 15% HCl solution, and the corrosion inhibition performance was evaluated by using weight loss, electrochemical measurements, scanning electron microscope (SEM), quantum chemical calculation and molecular dynamics simulation (MDS). The results show that synthesized β-HA showed excellent corrosion performance compared with MHB and PE for carbon steel in 15% HCl solution compared with MHB and PE, and the inhibition efficiency increased with increasing concentration of the inhibitor. The inhibition efficiency of β-HA at 8 mmol/L reached the maximum value 94.08%. The inhibitor acted as mixed-type inhibitor via blocking both the anodic and cathodic reaction. The adsorption of inhibitors on N80 steel surface obeyed Langmuir adsorption isotherm, and the process contained chemisorption and physisorption. The ΔG ads of β-HA was −28.81 kJ•mol −1 under the standard atmospheric pressure. Moreover, the theoretical calculation parameters revealed stronger combination and higher interaction energy for inhibitor β-HA comparing with MHB and PE, further demonstrating the correlation between the theoretical and experimental results.