Two Mannich base corrosion inhibitors, ZJ-1 and ZJ-2, were synthesized by Mannich reaction. The products were characterized by infrared spectroscopy. Corrosion inhibition effect of these two inhibitors on P110 steel were studied by means of polarization curve measurement, electrochemical impedance spectroscopy and molecular dynamics simulation. While the relevant corrosion inhibition mechanism and adsorption behavior were also discussed. Results showed that the two synthesized corrosion inhibitors presented obvious corrosion inhibition effect on P110 steel in 1 mol/L NaCl+CO₂ environment, however, ZJ-1 had better corrosion inhibition effect with a corrosion inhibition efficiency up to 92.06%. These two corrosion inhibitors were belonged to mixed corrosion inhibitors based on anode control. Both the anode reaction and the cathode reaction were restrained in the corrosion process due to the adsorption film formed on the metal surface by corrosion inhibitors. Furthermore, ZJ-1 and ZJ-2 can displace water molecules and adsorb on the metal surface, the lone pair electrons provided by the active atoms N and O could form coordination bonds with the vacant orbital of Fe. Therefore, corrosion inhibitor molecules can be adsorbed on the metal surface and the corrosion inhibition effect is enhanced due to strong chemical forces of the bonds. Compared with ZJ-2 inhibitor, ZJ-1 inhibitor molecule has higher adsorption energy and better corrosion inhibition performance to the surface of Fe-based alloys.