Abstract: Through the research on the anti-shear property of an alpha-olefin polymer served as oil-soluble drag reducer prepared by bulk polymerization with Ziegler-Natta catalyst, it is found out that with the drag reducer having been suffered several shears, the drag reducing effect will decline sharply and to zero finally. Meanwhile, adding more drag reducer to the pipelining oil will contribute to good anti-shear property. The results obtained from the test can be used as an effective basis to direct pilot implementation and industrial application of drag reducer.