Abstract: In accordance with the constituent properties of oil pipeline system, the system can be divided into fundamental constituent units and an unsteady flow equation of oil in the unit is derived. And in comprehensive consideration of their boundary, connecting and initial conditions, through leading in a linearized coefficient the solving process is discussed by use of the Galerkin method. Such a method is of the properties of both analytical solution and numerical solution methods. When the divided pipeline unit is larger, an intuitive approximate analytical solution may be obtained; while the one is smaller, a more accurate numerical solution may be acquired. By contrast with the common analytic method, the method may be suitable for various pipe network structures and owing to the fact that the linearized coefficient may be calculated for various pipeline units and for different time interval, the accuracy of the solution may be enhanced. Because the selected pipeline unit and time step may be larger or smaller and the size of each pipeline unit is different, the flexibility of acquiring solution is raised in comparison to the other numerical solution methods. Based on this, a computer program is made up and the practical simulation analysis is carried out for the local pipe networks in Huatugou-Golmud Oil Pipeline of Qinghai, a satisfactory result is obtained.