Abstract: Based on analyzing the comprehensive energy consumption of Maoming Oil Refinery, using process system integration optimizing approaches，optimizing the transformation, utilization and recovery of industrial energy in the whole plant were carried out. Some optimized solutions and measures for saving energy were proposed and mostly were realized, such as improvements in some main refining units, heat integration among units, proper using low-temperature heat, revamping storage-transportation and steam power system. Successful results were achieved, in 2011, the total crude processing capacity reached 14.5 million tons with processing loss of 0.38% only, the comprehensive energy consumption of the whole plant was reduced to 2 071 MJ/t, in which saving electricity more than 20 million kWh and steam 255 kt.