This research aims at determining effects of pH on akridin adsorption by montmorillonite, knowing Akridin concentration variations on the adsorption of montmorillonite, and knowing adsorption patterns following Freundlich isotherm or Langmuir isotherm. The sample of montmorillonite was saturated using KN03 solution and thus became K+- montmorillonite. Akridin adsorption by montmorillonite was done in three stages which were the kinetics adsorption to determine the time required in the process of akridin adsorption, the adsorption edge to determine the effect of pH on the adsorption, and adsorption isotherms to determine the effect of Akridin concentrations added to the adsorption capacity of montmorillonite. Adsorption process was carried out at pH 4, and the Akridin concentrations of 1 x 10-, 1 x 10-4, 5 x 10-4 with a medium of KN03 electrolyte of 5 mM. The measurement was carried out using UV-Vis to determine the concentration of akridin residue, while XRD was used to determine changes of space d (00l) on montmorillonite. The amount of adsorption capacity of montmorillonite in Akridin at pH 4 was obtained using the calculation of chemical analysis. The maximum adsorption capacity obtained in this study was 1.2 x 10-5 mof/m2. The pattern of adsorption in this study could not be categorized as following Langmuir pattern. XRD spectrum showed that there was a decrease in space d amounted to 1, 841.