A new superstructure form of heat exchanger networks (HEN) is proposed based on expert system (ES). The new superstructure form is combined with the practical engineering. The different investment cost formula for different heat exchanger is also presented based on ES. The mathematical model fur the simultaneous optimization of network configuration is established and solved by a genetic algorithm. This method can deal with larger scale HEN synthesis and the optimal HEN configuration is obtained automatically. Finally, a case study is presented to demonstrate the effectiveness of the method.