Two kinds of imidazoline inhibitors with different hydrophilic groups, i.e. hydroxyethyl imidazoline (HEI-11) and aminoethyl imidazoline (AEI-11), were used for resisting CO2 corrosion of N80 steel in single liquid phase and liquid/particle two-phase flow. Inhibition performance of these imidazoline inhibitors for CO2 corrosion of N80 in 3% (w) NaCl solution was investigated using polarization curve and electrochemical impedance spectroscopy under static and flow conditions. The results showed that the inhibition efficiency under both static and flow conditions increased according to the following: HEI-11>AEI-11. The inhibition performance of both inhibitors was severely degraded by single liquid phase and liquid/particle two-phase flowat5m·s-1. Additionally, quantumchemical calculation was carried out to correlate the inhibition performance of both inhibitors with their chemical structures and to explain the inhibition mechanism. The theoretical calculation was in od agreement with experimental results.