逆物流的主要目的為產品的回收及資源的再利用，已使用過的產品可以被回收並可拆解成回收料，在逆物流的系統中，產品可藉由使用新原料來進行新品的製造，亦可使用回收料來進行再製造，而且這兩種製造方式所生產出的產品並沒有差異，然而，回收的作業往往伴隨著極大的不確定性，如：回收品的數量難以掌握、回收品的品質參差不齊…等，因此，如何進行產品的回收和掌握回收品數量為逆物流系統中的重要課題，此外，產品的生產數量包含新品的製造數量和回收品的再製數量，所以在擬訂存貨策略時，需考量到新原料和回收料的供給是否充足，對此本論文將針對在隨機的回收數量下，找出最佳的生產數量，而此生產量使得生產成本為最小。 The stochastic return quantity of used products influences the inventory policy in reverse logistics. The goal of reverse logistics is to recycle the materials and remanufacture the used product into new one. In addition, the product can be remanufactured from return materials or manufactured from new materials. The important assumption is that the remanufactured items are as good as new. Since remanufacturing needs the return materials that are disassembled from used products, the stochastic return quantity of used products affects the number of recoverable items (or called return materials). Although the number of recoverable items is uncertain, the firm has to decide the order quantity that includes remanufacturing items and manufacturing items. Therefore, this study wants to find that the number of remanufacturing items and manufacturing items have to be prepared for each period. In other words, the object of the thesis is to determine the optimal production quantity under stochastic return quantity in each period. Of course, the optimal production quantity minimizes the total expected cost.