傳統經濟訂購量受到許多學者廣泛的討論，其假設製造過程中所有製造的產品的品質皆為完美的，但在實務上無法達到。在生產過程中常因為品質管控不良、機器設備老舊、操作人員的影響等因素造成產出不符合要求的不良品。為了更貼近實務上的需求，加入不良品的產生較能符合真實情況。本研究主要目的為探討額外費用投資降低不良率之品質提升和更新理論觀念導入非完美品質生產存貨系統，加入兩種考量因素以增加存貨模式的實用性。第一種為非完美品質生產系統考慮額外投資費用降低不良率之品質提升；第二種因素為更新理論觀念探討非完美品質生產系統過程來推導目標函數。因此，本研究將非完美品質生產存貨系統加入兩情況的研究，推導出最佳存貨策略，期望將此存貨策略提供給企業做為決策參考依據，幫助企業增加利潤與提高競爭力。

The classical economic quality is subjected to many discussions with extensive scholar, its assumption manufacturing process all products quality of manufacturing are all perfect, but perfect quality is unrealistic in most industrial applications. In the production process often because the quality control is bad, old machinery equipment and operates the personnel's influence, it causes and produces imperfect goods. For coming close the need on the actual situation, joining the creation of imperfect goods more can match the realistic condition. The purpose of this study is to determine an optimal inventory policy for imperfect production system with quality improvement by renewal theory. Join two type of consideration factors with the function that increase the usefulness of the inventory system. Invest money to improve the production process. The imperfect production system with quality improvement by renewal theory. The mathematical expression for the expected profit function is derived and a solution procedure is proposed to determine the optimal policy.