Living copolymerization of ethylene and propylene was catalyzed by a fluorine-containing bis(phenoxy-imine) titanium catalyst. A series of ethylene-propylene copolymers with different propylene contents were prepared and the copolymers were characterized by C-13-NMR, GPC and DSC. The copolymers were found to have the following characteristics: (1) Molecular weight distribution of the copolymer is rather narrow; (2) There exist only isolated propylene units distributed along the polymer chains even at propylene content as high as 14.9 mol%; (3) The distribution of ethylene sequence are not homogeneous. Insertion of propylene changes from 2,1-insertion in homopolymerization into 1,2-insertion when the preceding unit is ethylene.