Abstract: Mixing with light oil is one of major transportation approaches for dehydrated heavy oil. In order to optimize the heavy-light ratio and reduce the energy consumption for transporting heavy oil, a mathematical model based on the relationship between consumption of kinetic energy and heavy-light ratio is established to optimize the consumption of kinetic energy during heavy oil transportation. This model was used for analysis and calculation for the Chennan Central Processing Station, Shengli Oilfield. The results indicate that, mixing heavy oil with light oil is a very effective way to lower viscosity, by which the viscosity of mixed oil can be reduced greatly; however, with the increase of heavy-light ratio, the addition of light oil will increase the flow rate of mixed oil, thus increasing the consumption of kinetic energy. Therefore, there is a best heavy-light ratio for the mixing process. The consumption of kinetic energy will increase if the heavy-light ratio is too high. With the log-log model and the calculation approach of viscosity equivalent, and considering the properties of heavy oil and light oil, the best heavy-light ratio can be worked out.