Hierarchically mesostructured materials have been successfully synthesized via a facile route using amphiphilic block copolymer polystyrene-b-poly (acrylic acid) (PS-b-PAA) and cetyl trimethyl ammonium bromide (CTAB) as dual templates. It is found that the dimension of spherical micelle-like aggregates of PS-b-PAA could be adjusted by changing the kind of solvents. With N,N-dimethylformamide (DMF) as solvent, spherical micelle-like aggregates with an average diameter of 35 nm were obtained, and bimodal mesoporous materials (BMM) possessing large pores of similar to 35 nm and small pores of 2.5 nm could be prepared. As the solvent was changed to N,N-dimethylformamide (DMF)/tetrahydrofuran (THF) (v/v = 1:1), the average diameter of the spherical micelle-like aggregates of PS-b-PAA was increased to 200 nm, and hollow mesoporous spheres (HMS) with 200-nm hollow cores and 25-nm shells were thus achieved.