Imidazoline quaternary ammonium salt corrosion inhibitor was synthesized from oleic acid, diethylenetriamine and benzyl chloride. The structure of quaternary ammonium salt was characterized by FT-IR, ₁^H-NMR. The ions were exchanged into the Na-montmorillonite (DK0) layer to prepare the corrosion inhibitor modified organic montmorillonite. The structure, composition and release properties of QACDK0 were characterized by XRD, TGA and UV-Vis. The results showed that the insertion of quaternary ammonium salt inhibitor increased the spacing of montmorillonite layers from 12.8 ? to 39.8 ?, and the load of inhibitor in montmorillonite was about 39.0 wt%. In order to study the effect of different nano-clay particles on the corrosion resistance of water-based epoxy coating, epoxy resin/montmorillonite composite emulsions were prepared by phase inverse method with the incorporation of QACDK0, DK0 and commercially available common organic montmorillonite blended with epoxy resin E-51. DLS and Zeta potential were used to characterize the stability of epoxy emulsion. The Zeta potential of imidazoline quaternary ammonium salt corrosion inhibitor modified montmorillonite/epoxy emulsion was -27.8 mV, indicating the highest stability. Electrochemical impedance spectroscopy (EIS) test demonstrated that after 30 days of immersion in corrosive medium, the impedance modulus of the anticorrosive coatings prepared based on QACDK0 remained the highest, with a high impedance value of 2.29×10₈ ^Ohm.cm₂^{, indicating that the release of quate}rnary ammonium salt corrosion inhibitor made the coatings have better active anticorrosive properties. In the test of neutral salt spray resistance, the grey coating containing pigment corresponding to QACDK0 salt spray resistance time, which verified that the coating has good salt spray resistance performance. In addition, the coating surface is flat and compact, which was beneficial to good barrier performance.