Abstract: There has been a fault for ages in analyzing the operating state of batching in oil pipeline, that the hydraulic behavious during mixture passing pumping stations is explained and described with "system operating point popping", Based on the diversity of the nature and level of unsteadiness, the operating state of batching should be divided into three regions, surge—a period after mixture entering in head station; gradually changing—mixture passing intermediate stations; smoothly changing-mixture travelling along line. The boundary condition of mixture passing stations, matched the Characteristic Method for surge calculation, is provided. Following that come some analysis examples.