Abstract: An integrated fast reactor is a nuclear energy system consisting of a metal fuel fast reactor, a fuel regeneration facility (including dry spent fuel reprocessing and metal fuel manufacturing), and a waste preparation facility. It has the characteristics of integrated design, high fuel efficiency and low nuclear waste output. The technical difference with current nuclear power is embodied in the fact that the integrated fast reactor is a complete closed-loop fuel cycle system. The integrated construction strategy of one site and one plant can shorten the off-reactor circulation time to one year, and only a small amount of depleted uranium can be processed into new fuel and then re-entered into the reactor, so as to realize the rapid circulation and multiple circulation of fuel in the plant. The initial charge of the IWR is the spent fuel discharged from the MOX fuel fast reactor, which is processed by the dry reprocessing facility in the IWR and then sent to the metal fuel production line in the plant to be processed into metal fuel and loaded into the reactor for combustion. The economy of the integrated fast reactor is one of the main aspects of project decision-making, after the spent fuel is discharged from the reactor, processed into new fuel in the metal fuel production line, and then loaded into the reactor for combustion to achieve on-site self-circulation. At present, the economic analysis of nuclear power in China focuses on pressurized water reactors, while the economic analysis of fast reactors is mainly methodological analysis, and there are few case studies. International representative authorities and universities have provided economic evaluation methods, focusing on the cost-side analysis and less on the benefit-side analysis. Based on the characteristics of the closed fuel cycle of the integrated fast reactor, the economic evaluation method of the integrated fast reactor was studied by drawing on the economic evaluation methods at home and abroad, the economic evaluation model of the integrated fast reactor was proposed, and the range of values of the parameters in the model was analyzed, the LCOE model and financial evaluation model of the integrated fast reactor was constructed, and the preliminary economic evaluation was carried out from the cost-side and the benefit-side. The calculation results show that the LCOE of the first reactor is 0.279 yuan/(kW·h), and the internal rate of return (IRR) is 3.65%. With the support of the serialized learning effect, the LCOE shows a downward trend, and when the construction investment of the integrated fast reactor drops to 20 000 yuan/kW, its LCOE can be compared with that of the PWR, and the IRR of the project can reach the industry benchmark rate of return.