Abstract: In the design of Liu Ping-Yaodian Oil Transportation pipeline, because the elevation of the pipeline route drop is great in North Shannxi Yellow Soil Plateau, to make full use of drop potential energy of 650 m between the highest point and the terminal station and overcome the frictional resistance loss from the high point to terminal station along the total length of 10⁴ km, The program of reducing pipe is worked out to resolve high inlet pressure in the terminal station so as to realize the objective of "one pump through the line". Meanwhile, owing to decrease of intermediate boosting pump station, power consumption, project investment and operating post are reduced and pipeline system safety and reliability are increased.