Abstract: It is a constraint multi-parameter optimization problem to determine cascade configuration parameters such as the distribution of the stage entering flows, the total number of stages and the position of feed flow on the condition that the concentrations of a target component in the product and waste flows are given. Using penalty function method, the constraint optimization problem was transformed into an unconstraint one, which was solved by the simplex method. The optimization method was applied to calculate the cascade in which the recycled uranium is enriched. The results show that the optimization method is convergent.