Abstract: Using ethylene and dodecene as polymerization monomers, a drag reduction copolymer of ethylene/dodecene was synthesized by solvent polymerization with n-Hexane as a solvent. The composite TiCl4/MgCl2 was used as a main catalyst and Al(i-Bu)3 as a cocatalyst. The structure and crystalinity of the copolymer produced were characterized by 13C-NMR and XRD techniques. The drag reduction performance of copolymer was evaluated in a self-designed indoor loop evaluation system with 1L reactor containing 600ml mixture of dodecene and n-hexane at -2℃. Under the optimum polymerization conditions: 0.4g main catalyst, n(Al)/n(Ti) of 80, V(dodecene)/V(n-Hexane) of 2/3, m(dodecene)/m(ethylene) of 912, the drag reduction rate is 45.45%. Compared with dodecene homopolymer, the crystallinity of the copolymer of ethylene/dodecene is significantly decreased due to the participation of ethylene, which helps to improve effective concentration of the copolymer in the oil, and to reduce the amount of drag reduction solution.