Abstract: Heat exchanger network(HEN) is one of the most important parts in the chemical production process. HEN optimization becomes an effective tool to save energy and keep sustainable development. There are many methods to optimize HEN. In principle, mathematical programming seems a comprehensive solution, while the pinch point method is still a handy tool, due to its simplicity and clear physical meaning. Special arrangement is required when phase change is considered in the system. The aim of this paper is to investigate six streams distributed in adjacent sections in an ethylene cracking process from the systematic perspective, as no heat recovery is involved, and only utility is matched to meet their temperature requirement in process. Problem table is used to determine the pinch point for the design of HEN. Due to the complex phase change of the mixture in the heat exchange system, the phase change section is converted into one or more streams with constant heat capacity flow rate according to its thermal load and material characteristics, so as to determine the temperature interval. In the traditional pinch point method, △T_min is found as 11 ℃, and it is determined to be 9 ℃ with the consideration of carbon emission. The average pinch point is determined by problem table at 83.8 ℃. Under this condition, the minimum thermal utility required by the heat exchanger network is 12727.27 kW, and the required minimum cold utility is 38719.59 kW. The total annual cost is reduced by 2620585.49 /a, and the carbon emission is reduced by 61453.50 t/a. According to the design principles of pinch technology and stream matching criteria, the energy-efficient heat exchanger network structure is obtained.