Abstract: To reduce Dower consumption and toss of light fraction of crude oil, a schem e in tight line semi pipe flowing transportation for Alshan--Saihanthara Oil Pipeline is constituted and put into effect.The semipipe flowing scheme, which the pipeline located at the peak point with slack flow downstream is divided into two sections that the pressures within the two pipe's section and the pressu re fluctuations between upstream station and d.wnstream station are independent, can realize the tight line transportation of crude oil under the condition of floating line transportation. This paper describes the sc heme involved in hydraulic calculation, scheme constitution, step of scheme implementation and economic pro fits analysis, which can provide a useful practice to other pipeline in design.