Abstract: The mesoporous SiO2 was synthesized by template P123 and modified with γ-aminopropyl triethoxysilane (APTES). The pore structures and degree of order of cationic mesoporous SiO2 were characterized by low-angle X-ray Diffraction (XRD), nitrogen adsorption-desorption (BET) and transmission electron microscopy (TEM). The functional group was analyzed with Fourier infrared spectrum (FT-IR). The adsorption of HPAM on cationic mesoporous SiO2 was studied. The results show that the cationic mesoporous SiO2 is successfully prepared and possesses ordered hexagonal structure. The BET surface area and pore size is 66.3m2.g-1 and 6.9nm, respectively. The optimum adsorption conditions for the solution with initial pH 6.5 are the adsorption time of 120min, 50℃, solid-liquid ratio of 4:1. Under these conditions, the adsorption capacity is up to 1340mg/g.