Abstract: On the basis of the orthogonal experiment, this paper has analyzed the influencing factors of the adsorption of clay via laboratory batch tests, which provides a base for the investigations on cation adsorption of clay. After the batch tests, geotechnical characteristics of cation-contaminated clay are studied. We get the changing trend of the geotechnical characteristics. It is found that the cation adsorption capacity of clay in the single cation liquor is higher than in the multi cation liquor; the higher valence cation has stronger competition in the multi cation liquor; the plasticity index of clay increases with cation content and the strength of clay reduces progressively with the total cation content.