本研究像以傳統經濟批量模式為基礎，探討需求固定的情況下，考量預知特定時點貨品價格上漲且存貨空間受到限制時，決定最適訂購策略之問題，以達到存貨總成本最小化與節省成本極大化為目標。若內部倉庫放滿時，仍然達不到存貨總成本最低時即可考慮外租倉庫。本文以傳統EOQ之假設，建構節省成本額之數學模式，進行最通訂購量之探討，再經由範例分析驗證最適訂購量的正確性，最後提出四點結論，作為企業進行訂購決策之參考。

This article formulate a mathematical model, in which the price of goods is going up in the near future and the warehouse capacity is constrained, how to decide the optimal ordering policy for cost saving is an important issue. We assume that decision maker can order at any time, but we don't allow backordering, consider that the warehouse capacity is constrained. We can consider the rental warehouse when our internal warehouse is full. We construct mathematical cost saving model. By applying the optimization technique, we find out the optimal ordering quantity to minimize the total inventory cost or cost saving. Finally four conclusions are drawn for future applications and studies.