Abstract Micro-emulsion usually consists of water, oil, surfactants and co-surfactants, and each component has an effect on the phase behavior and solubilization of the micro-emulsion. When the surfactant in the micro-emulsion system is quaternary ammonium cationic Gemini surfactant, the surfactant mainly combines with the anions in the salt. With the increase of salt concentration, the phase transformation of Winsor I → Winsor III → Winsor II occurred, but the optimum salinity and salt width are different because of the type of salt. The effects of 5 different kinds of monovalent anions, including C6H5SO3−, I−, Br−, NO3− and Cl−, on the phase behavior and solubilization of quaternary ammonium cationic Gemini micro-emulsion are researched by Winsor phase diagram. It is found that the effects of organic anions C6H5SO3− and I− on the phase behavior and solubilization of quaternary ammonium cationic Gemini micro-emulsion are most significant, and the effects of Br−, NO3− and Cl− are less significant. Meanwhile, when the optimum solubilization is achieved, the amount of sodium benzoate is the least, indicating that the organic anion has stronger self-organization behavior with quaternary ammonium cationic Gemini surfactants.