Abstract: Drag reducer is a kind of high molecular polymer used in oil pipeline to increase the throughput or decrease the operation pressure. In this paper, EP—W203, a copolymer of α-olefins was prepared. A test loop in the laboratory was utilized to evaluate the performance of drag reducers. The drag reduction of EP—W203 were determined under different test conditions. The loop test results have shown that EP—W203 has remarkable drag reducing effect only under a concentration of mg/L in the fluid. A field test has been conducted in Huatugou—Golmud pipeline of Qinghai oil field. The test results have shown that at a dosage of 7 mg/L, the drag reduction rate is 34.99%. And at a dosage of 10 mg/L, the drag reduction rate is 41.28%. At this injection concentration, the pipeline throughput is anticipated to be increased from 180×10⁴ t a year to 240×10⁴ t a year. When at a dosage of 20 mg/L, the drag reduction rate is 57.05%, that is equal to the performance of LP, which has a drag reduction rate of 57.4%. The evaluations of EP—W203 indicate that the performance of EP—W203 is remarkable and is equivalent to that of LP. EP—W203 has great application potentiality in oil pipeline transportation.