Abstract: In order to explore a reasonable optimization method for the resistance of flue gas pipes, the flue gas pipes before and after the induced draft fan of a 660 MW unit of a power plant in Guangxi were studied to study the resistance characteristics and structure optimization of pipelines. The standard k-ε model is used to analyze the fluid dynamics of the flue gas pipes before and after the induced draft fan, and the resistance characteristics are studied and the optimization scheme is proposed. The results show that the three optimized flue structures proposed can improve the flow field and reduce the flue resistance, and one scheme using the deflector to optimize the flue resistance increases, in which the flue gas flow resistance of the inlet flue can be reduced by up to 123 Pa, accounting for about 75% of the original resistance, and the flue gas flow resistance of the outlet flue of the induced draft fan can be reduced by up to 242.4 Pa, accounting for about 54% of the original resistance.