The macroporous structure was formed in the wet gels by controlling the phase separation process induced by the hydrolysis and polycondensaton of alkoxysilane. Further bimodal porous silica with good mechanical strength can be obtained by aging process. The macroporous structure was formed in the wet gels by controlling the phase separation process induced by the hydrolysis and polycondensaton of alkoxysilane. Further bimodal porous silica with good mechanical strength can be obtained by aging process.