The invention refers to a method for selecting polymerization modifiers. More specifically, the invention discloses an olefin polymerization method which makes a catalyst composition including a transition metal compound, a cocatalyst and a polymerization modifier contact with a polyblend including at least one olefins monomer and styrene and is characterized in that the polymerization modifiers are selected from ethyl aluminum double (N,N- diphenylformamide), double (2,7- dimethyl-6- octylene-1- methyl) aluminum N, N- diphenylformamide.