蔬菜、水果、肉製品及海鮮等這類易變質品與我們的日常生活息息相關。在存儲過程中易變質品會隨著貯存時間發生腐爛、性能衰退和分解，從而降低產品的新鮮度或者數量。本文從批發商的角度討論了擁有兩類分別是常數需求和庫存依賴需求的零售商的易變質品庫存模型。假設了兩類零售商有不同的缺貨成本和常數變質率，分析了總成本的構成，以總收益最大化爲目標，建立了該問題的優化模型，分析了總收益函數的性質，討論了如何確定最優訂貨週期，計算實例驗證了該方法的有效性，並給出了缺貨成本與訂貨週期的關係。

Perishable products widely occur in daily production and life, such as vegetables, fruits, meats, seafood, whose freshness level are decreasing and inventory are losing by deterioration (damage, spoilage, dryness, vaporization, etc) as time elapsing. In this paper, an inventory model with two retailers is discussed, whose demands for perishable products are respectively constant and stock-dependent. Two retailers sell the same perishable product ordered from the single wholesaler. In the model, constant deteriorating rate is considered, shortages are allowed without backlogging, and the total profit is analyzed. Shortage cost rates and selling price are different. The necessary conditions of the existence and uniqueness of the optimal solution are shown. An optimal solution procedure to find the optimal replenishment policy is presented, and concavity conditions are discussed.