In this article we collected bentonite samples from cities including Weifang, Laiyang and Laixi in Shandong province of China and tested their cation exchange capacity (CEC) . Orthogonal tests were designed to optimize the process parameters on acid activation. There are three quality indexes including activation degree(AD), bleaching capacity(BC) and decolorization ratio(DR) in the tests. Correlation between CEC and three quality indexes, CEC and activation strength were studied, as well as the correlation among the three quality indexes. The results show that AD and DR decrease with CEC’s diminution, while BC has no regular change with CEC’s decrease. In order to get large value of the three quality indexes, the activation strength needs increase along with the CEC’s diminution.We also find that the correlation among the three quality indexes vary with CEC. Judging by CEC, their correlation and the least energy consuming, activated clay of the best property and the various application can be prepared.