Abstract: Taking Dongxin sulphur-bearing oil pipeline as an example, the study on the rheology of mixture of oil samples produced from Gudao and Qinghe oilfield has been finished. A novel formula for calculating the viscosity of the combined oil is presented. A mathematical model for the energy-saving has been establisled on the basis of the combination of the optimazition of pipeline operation parameters and the research of energy-saving programmes. The optimal operation software for Dongxin sulphur-bearing oil pipeline is developed. The software can be used to guide the technical reform of pump station of by-pass hot oil pipeline, optimal operation after reform as well as transporting oil plan. The software has been used to calculate the reform program and optimal operation program. The results are satisfactory.