Inhibition performance and synergistic effect of an imidazoline derivative, namely 1-[N,N-bis(hydroxylethylether)-aminoethyl]-2-stearicimidazoline (HASI) with tetraethylenepentamine (TEPA) on the corrosion inhibition of steel rebar in an artificial concrete pore solution containing 3.5%NaCl were investigated using linear polarization, potentialdynamic polarization and electroch-emical impedance spectroscopy (EIS) techniques, while molecular dynamics (MD) simulation was employed to explore the co-adsorption behavior of the composite inhibitors on the metallic iron surface. Results indicate that after the addition of inhibitors, the corrosion current density of steel rebar was reduced and the corrosion resistance of steel rebar was enhanced. With increasing content of HASI in the composite inhibitors, the inhibition efficiency gradually increased, the corrosion potential shifted significantly to negative, and therewith a more positive pitting potential and a wide passive region were observed in comparison with that in the blank solution, which reveal that the chloride-induced corrosion on steel rebar was effectively retarded by the composite inhibitor, in other words, HASI and TEPA exhibited a good synergistic effect on the corrosion inhibition of steel rebar in the artificial concrete pore solution. MD results show that molecules of HASI and TEPA could simultaneously be adsorbed on the metallic iron surface to form a more compact protective film and consequently became a barrier to hinder the access of aggressive species in the corrosive solution to the metal surface, thereby to effectively inhibit the corrosion of steel rebar.