A water-soluble cationic hydrophobic monomer, N, N-dimethyl octadecyl allyl ammonium bromide, was synthesized by using 3-bromopropene and N,N-dimethyloctadecylamine in acetone. Using water as solvent, a partially hydrolyzed polyacrylamide containing high proportion of hydrophobic monomer was synthesized and aimed to be used as drag reducer agent (DRA). NMR spectrum confirmed that structure of the product was consistent with the preset and hydrophobic monomer accounted for 1%, molecular weight of the drag reducer was 1.22×107 g/mol which characterized by laser light scattering. The critical association concentration measured by the viscosity method is 0.28%. Friction of diluent solution at different flow rates in the pipeline was tested, and drag reductions (DR) were calculated by using the clear water as blank group. When the concentration of DRA is 0.13%, DR can reach up to 72%. In salt water, DR decreases. By increasing concentration of DRA, DR can be increased. When the amount is 0.2%, DR is up to 70.06%. It is known from SEM that network structure formed by DRA in water is the direct cause of the resistance reduction of DRA.