Hierarchical mesoporous silicas containing two kinds of mesoporous size are successfully synthesized using the simple evaporation-induced self-assembly (EISA) strategy. Two blocks of hydrophobic segments (PE and PCL) in the poly(ethylene-block-ethylene oxide-block-?-caprolactone) (PE-PEO-PCL) triblock copolymer are involved in the two types of mesopore after calcination, the PE segment being attributed to the face-centered cubic (fcc) morphology (spherical pores) and the PCL segment attributed to the tetragonal cylinder structure (cylindrical pores).