In this paper, the order of addition in the preparation of aluminum salt modified bentonite process is changed as compared with the traditional method. The expansion performance in aluminum salt modified bentonite is enhanced, and the modified bentonite is characterized by SEM, XRD, particle size distribution and FTIR and compared with the raw material Na-bentonite to deduce the mechanism of modification. Finally, the appearance is observed and the performance of adsorption is investigated. It is shown that, compared with the traditional method, the preparation of aluminum salt modified bentonite is relatively simple, and the addition order is different from that in the traditional method in that the bentonite is first mixed in water and then the modified agent is added. The modified bentonite has an efficient effect on silicate removal which can reach up to 99%.