The　polymerization　of　styrene　in　reverse　atom　transfer　radical　polymerization　(RATRP)　microemulsions　with　cetyltrimethyl　ammonium　bromide　(CTAB)　as　surfactant,　CuBr2　as　catalyst　and　2,　2′-bipyridine　as　ligand　respectively　in　the　presence　of　different　initiators　was　studied.　The　results　show　that　the　system　with　azobi-sisobutyronitrile　(AIBN)　as　initiator　is　unstable　during　polymerization.　In　the　system　with　potassium　persulfate　(KPS)　as　initiator,　the　degree　of　conversion　drops　sharply　with　increase　of　the　amount　of　catalyst/ligand　complex.　While　KPS-tetramethylethylenediamine　(TMEDA)　is　used　as　complex　initiator,　the　loss　of　control　in　initial　pe　riod　is　weakened　at　lower　polymerization　temperatures　and　the　atom　transfer　between　the　active　and　dormant　species　is　heightened　at　higher　polymerization　temperatures.　The　polydispersity　indexes　(PDF)　of　relative　molecular　mass　of　the　products　are　below　1.5.　The　size　of　latex　particles　is　on　nano　scale.