An Optimized Method for Two-echelon Inventory System Based on Stochastic Lead Time

On the condition that demand and lead time are both randomly,the article studies a simple two-echelon inventory system,that is,the optimization problem of one supplier and one retailer.They both use s,Q strategy to manage inventory,and both the order quantity Q_r and Q_s are constant,on this basis,to get the system′s optimization strategy s_r,s_s,optimization function of the system has been established in the object of minimizing expectation total cost of system running during each planning period,and at last solving arithmetic and numerical example have been given.