Batch sorption experiments were conducted to investigate the sorption characteristics of Cs, known for the primary target of safety assessment in low-level radwaste disposal, onto domestic rocks such as Granite and Tuff. A response surface analysis method was applied to quantify the effect of 3 independent variables ([Cs], [Vol/Wt], [pH]) on the sorption. Ac a result, initial Cs concentration appeared to be the most important variable within the range of the study. A significant effect of [Vol/Wt] on Kd was observed. The sorption of Cs was pH-insignificant. The sorption extent of nuclides onto tuff was more significant than that onto granite. The pH-insignificant sorption behavior of Cs was discussed in terms of the surface electrical properties and the solution chemistry. The sorption tendency of nuclides onto geomedia studied was interpreted by adopting the water structure modification theory.