Abstract: The applied experiment of BEM-5 flow improver on Hekou-Nianhua crude oil pipeline in Shengli Oilfield is made. With a capacity of 50×10⁴ t/a, this ϕ273×7 mm pipeline is 51.4 km long with one heated pump station and 5 heating stations installed along the line. The effect study on the reduction of viscosity and pour point of crude oil with this flow improver is conducted. Based on the experimental results, the operation scenario of the pipeline during the winter and summer is optimized. The applied results show that this flow improver has a good effect on the reduction of viscosity and pour point, and the pipeline can be operated under the temperature-drop conditions with the remarkable economic profits.