Abstract: For further understanding the wettability alteration induced by organic salts, series of bis-imidazolium salts (EBMI, TBMI, HBMI, OBMI and DBMI) were employed for investigating their adsorption behavior and wettability alteration on vermiculite (Vt) by experimental and theoretical studies. The characterization results indicated that all bis-imidazolium salts had been loaded on Vts. The adsorption results showed that EBMI, TBMI, HBMI, OBMI and DBMI on Vt reached equilibrium of 0.159, 0.156, 0.145, 0.114 and 0.084?mmol?g?1 around 30?min at 25?°C, respectively, which were sensitive to ionic strength and pH. Langmuir, statistical physical modelling and pseudo-second-order models could be well fitted with the adsorption data, and thermodynamic parameters suggested that the adsorption processes of bis-imidazolium salts were endothermic and spontaneous, indicating that the resultant bis-imidazolium salts could be self-assembled onto Vt in the form of the monolayer. Results of molecular dynamic simulation showed that bis-imidazolium salts were adsorbed on Vt with the lying-flat configuration, and the electrostatic interaction acted as the main interaction mechanism, which were consistent with that obtained experimentally. Changes of wettability of Vt induced by bis-imidazolium salts were verified by capillary rise experiments. Interestingly, the wettability of organo-Vts varied with the spacer length and the order was as follows: EBMI-Vt?