A novel imidazoline derivative has been synthesized and its molecular structure has been confirmed by IR, Raman, elemental analysis and NMR, the molecular structure of the inhibitor is similar to that of the previous research. In this paper, the inhibition performance and inhibition mechanism of the three inhibitors (SMID, SMIS and SMIF) in concrete simulation solution are analyzed and compared. The corrosion inhibition efficiency of SMIF (96.02 %) > SMIS (93.62 %)>SMID(93.01 %) in weight loss experiment, the SMIS of electrochemistry of Nyquist and potentiodynamic polarization were 89.72 % and 92.03 % respectively, which indicated that SMIS had good corrosion inhibition effect. Electrochemical experiments show that the SMIS belongs to anodic type, and the mechanism of SMIS can form a protective film on the surface Q235 and inhibit the charge transfer. The results of FTIR, EDS and XPS show that SMIS can be adsorbed on the surface of Q235, which is also confirmed by density functional theory (DFT) and molecular dynamics simulation (MD).