The purpose of this thesis is to overcome the shortcomings of the existing system which lacks cost-conciousness and does not consider the essentiality or the importance of an item, and to seek the method of providing effective, efficient and economic supply which is the objective of the military inventory management. Selective management technique and lot size model whose demand, and order and shipping time are distributed, are intorduced, and required distributions and parameters are analyzed. Finally hypothetical data are utilized to obtain the model output, which are compared with the existing model and analyzed.