Abstract: The reproduction point based production and inventory control policy is analyzed as the starting point for further research,followed by the analysis on the quantitative relation between service level and stocks of the production system in stochastic-demand environment,and the average inventory in planning periods is invited into the aggregate production planning model.The planning out put in every period is stochastic variables having the same distributions with the product demands.By computing the optimal reproduction points and service levels,the optimizingaim of this model is to determine the optimal production intervals for each product in each period.Solution algorithm is proposed and an numerical case is used to validate the model.

Key words: aggregate production planning, reproduction-point, service level, optimizing model