Poly(butyl methacrylate-divinylbenzene) (PBMA) microgels were prepared using monodisperse polystyrene seed particles by the dispersion polymerization technique at 70∼80℃ with 2,2`-azobis (2,4-dimethyl valeronitrile) (V-65) as an initiator. The effects of polymerization parameters such as the monomer/seed and diluent/monomer ratios, the concentration of crosslinking agent, the type of diluent on the formation of porous structures, average particle size and pore size distribution were investigated. The physical features of the polymer particles such as the specific surface area, pore size, pore volume and porosity depend on the amount of the seed, crosslinking agent, diluent and the type of diluent. Therefore, the physical features of the polymer particles could be controlled by the physical properties of the particles.