Photopolymerization of MMA in micellar solution was studied kinetically using ben-zophenone／triethylamine system as initiator．Catalytic effects of miceUe in the polyme-rization with different type of surfactants，such as SDS，CTAB and Triton X-305，have been observed，in which ionic micelles are more elfectire ones．The polymerization rate and molecular weight of polymer increases with increasing coneentration of mieelle in solution．The solubilization aites of BP／TEA／MMA system in ionic mieelles have been established by UV and 1H nmr spectra．The results indicate that the reaetion takes place in the mieelle-water interface (Stern layer)．The orientation of the solubilized monomer molecules in the mieelles will result in an increase of the regularity of con- figurational sequence in the PMMA．