Abstract: Energy saving is one of the pressing duties the enterprise confronted. The energy integration of alkylation unit in a phenolacetone plant is optimized by using pinch technology in this paper. The results show that energy saving potential of the current heat exchanger network is 28.2%. After analysis by pinch technology, the unreasonable match of heat exchanger is found. After the investigation on the current heat exchanger network, the retrofitting scheme of the network, in which the maximum heat recovery is taken into account, is put forward. The retrofit scheme for the heat exchanger network can save heat 3 908.58 kW, while the payback period of the investment is only 3 months.