Abstract: Based on the characteristics of cold and hot streams in crude distillation unit (CDU), using pinch technology, the streams of the heat exchanger network (HEN) in CDU are divided into four categories: hot streams above the pinch, cold streams above the pinch, hot streams below the pinch and cold streams below the pinch. The bottlenecks of the HEN are analyzed, such as the number of cold stream is much less than that of hot stream and the heat source above the pinch is deficit while the heat source below the pinch is surplus. Therefore, an optimization strategy of HEN based on the plus/minus principle is presented in this paper. A case study of this proposed strategy is carried out in the HEN of an industrial CDU with a capacity of 5 Mt/a. Results show that the final temperature of heat-exchanged crude oil is increased by 33 oC, the comprehensive energy consumption of the whole CDU is decreased by 26 MJ/t, which indicates that the energy saving effect of this proposal is significant.