Abstract A novel type of amphiphilic diblock copolymer consisting of butyl methacrylate (BMA) block and glycidyl methacrylate (GMA) block (BG copolymer) was successfully synthesized via atom transfer radical polymerization (ATRP) and then utilized as a phase separator to control the porous structure of poly(butyl methacrylate-co-ethylene dimethacrylate) (poly(BMA-co-EDMA)) monoliths. It has been found that the addition of the BG copolymer had a great impact on the polymerization of the monoliths. When the amount of the BG copolymer added into the synthesizing solution was changed, the porous structure could be varied from aggregated microglobular structure to well-defined three-dimensional (3D) skeletal structure. The porous structure was characterized by scanning electron microscope, mercury intrusion porosimetry and nitrogen adsorption measurement. Finally, the separation of proteins demonstrated its potential applications in proteome research.