Abstract: For long-term stable production of isotopes, without considering the technological innovation of the industrial chain, the utilization rate of cascades is the key factor that directly affects the cost of isotopes. Therefore, through reasonable cascade separation and structure design, the cascade utilization can be improved as much as possible and the isotope cost can be reduced. In the multi-component isotope separation, there is no concept of ideal cascade, and there is no universal design method for the time being. Therefore, the quasi-ideal cascade design combined with the round-up idea of scale cascade is used to study the cascade design method of multi-component isotope separation. The results show that the utilization rate of the designed cascade can increase the production capacity by about 20% compared with the universal rectangular cascade, and the separation cost can be greatly reduced. This design method can be used in the design of multi-component isotope separation cascade for long-term stable production.