Abstract: Aiming at the problems of PWR plants with 18 months refueling model, such as low batch discharge burn up and low fuel utilization, two types of fuel assemblies enriched in 4.45% and 4.95% are adopted for the fuel management with 18 months refueling in this paper. The results show that, by optimizing the layout of the fuel assemblies and burnable poison, dual-enrichment 18 months fuel cycle can meet the design criteria of current 18 months cycle fuel management. In the same cycle length, it can achieve a higher average discharge burn up and a fewer fuel cost to get a better economy benefit.