Polyarylether dendrons as macroinitiators for the "living"/controlled free radical copolymerization of N-phenylmaleimide (PhMI) and styrene (St) have been demonstrated. The copolymerization was carried out in bulk or anisole with CuBr/bipy catalyst at 100-130℃. It is found that the resulting copolymers possess predetermined molecular weights and narrower polydispersities (1.18 < Mw / Mn < 1.32). The effects of reaction temperature and monomer feed on the copolymerization kinetics were investigated in detail. By using the Fineman-Ross method, the apparent monomer reactivity ratios for the atom transfer radical copolymerization of PhMI and St were determined to be rPhMI = 0.0207, and rSt = 0.0484, respectively.