Hydrophobicity, high viscosity, and dispersion are important properties for organo-montmorillonites, and all organo-montmorillonite configurations have yet to be fully characterized with respect to this property. High-viscosity montmorillonite (Mnt) is useful in gels and as an adsorber. The current study focused on modifying Mnt using organic cations and anions of various chain lengths in batch experiments with various concentrations and ratios. The viscosity of organic Mnt reached up to 395 mP.s. Molecular dynamics simulations and X-ray diffraction (XRD) were used to identify the conditions and arrangement of organic cations and anions in the Mnt interlayer area. The intercalation mechanism of organic cations and anions was also determined, providing a theoretical basis for the preparation of high-viscosity Mnt.