In this study, the electrochemical injection (ECI) process of imidazoline quaternary ammonium salt (IQS) corrosion inhibitor into chloride-contaminated reinforced concrete and its influence on the material properties of concrete were investigated.The ECI treatments were conducted with an applied current density in the range of 1 -5 A/m2 for periods of 7-28 d.Control experiments, in which the electrochemical chloride extraction (ECE) were also conducted for the similar experimental conditions with ECI, but in the absence of corrosion inhibitor.Before and after the ECI treatment, the concentration profiles of the IQS corrosion inhibitor, Cl-, Na+ and K+ in concrete were determined by X-ray photoelectron spectroscopy (XPS);the alterations of chemical composition,amount and morphology of the hydration products in concrete were assessed by X-ray diffraction (XRD),scanning electron microscope (SEM) and differential scanning calofimeter-thermogravimetric analysis (DSC-TG).The microstructure of the mortar derived from the concrete was evaluated by mercury intrusion porosimetry (MIP).