Abstract: Daqing to Tieling Parallel Oil Pipeline is the largest oil pipeline system in China. It is of great significance to enhance the economy of the system by optimizing operation to reduce the energy cost. In this paper, the optimal scheme for the steady operation of the system is computed and analyzed for the given flow rates by means of QTOPT, a software developed by ourselves specially for the optimal steady operation of Daqing to Tieling oil pipeline system. Some fundamental rules for the optimal operation are found from the computed results. Compared with practical operation scenarios, it shows that the optimal operation will reduce energy cost of the system to some extent.