Abstract: Kelamayi-Dushanzi Oil Pipeline, with the transportation capacity of 300×10⁴ t/yr, is consisted of three pipelines laid parallelly that the diameter of main pipeline is DN 150, the reduced pipe in DN 250/200/150 (build in 1962) and the pipe in DN 350 (build in 1991), the later pipe at present transport alternately Kelamayi blended oil and Lushi blended oil and the other two pipelines are in shutdown condition. To meet the needs of 300×10⁴ t/yr oil to Dushanzi Oil Refinery, the reduced pipe and DN 350 pipe are decided to put into operation to transport oil with combinational transportation process, that is alternated transportation technology. To avoid the oil blending, the theoretical analysis and hydraulic calculation are made. By means of technical reform in process flow and pumping equipments, the combinational transportation process is realized.