本篇論文的研究主要是以兩期、生命週期固定且銷售期短暫的季節性商品為主,並且在整體通路利潤最大化的目標下,探討在單一買方與單一賣方之二階層通路利潤模式。季節性商品因為銷售時間短故不可補貨,而且擁有在銷售初期消費者的保留價值較高,顧客願意付出較高的價格來購買商品,而隨著時間的消逝,消費者對產品的保留價值會因為產品已經過季、退流行了而降低的特性,故零售商必須在零售價格與顧客保留價值會相互影響而導致需求改變的考量下,於期初決定各期的零售價格與整個銷售期所需的庫存量,而因為不能補貨,故零售商亦必須承擔缺貨的成本。而本篇論文的目的是要建構出一個關於數量折扣和退貨的合約政策利潤模型,在數量折扣方面,本研究採用two-part tariff的兩階段式收費政策,而在退貨政策方面,本研究採用以退貨價全數退回未售完商品的政策,並藉由此二項政策的採用來平衡製造商和零售商的利潤,使雙方皆能夠在整體通路利潤最大的前提下,藉由合約政策的採用來達至雙贏的目標。 Seasonal goods industries are characterized with a short selling season and long manufacturing lead times. Actually, customers usually willing to pay higher price than those that buy toward the end of the season. In other words, when the retailer decides the amount of initial order quantity before the selling season must consider these product characteristics. The manufacturer in order to achieve the channel’s coordination usually constructs some contracts to get the win-win under channel’s max profit. In this paper, we consider a two periods inventory model under the two-part tariff policy and return policy. We assume that the manufacturer apply a two-part tariff policy to sell their products with retailer before the selling season, and the manufacturer also apply a return price to buyback the unsold products at the end of season. Our object is to provide a win-win coordination mechanism of contract–based policies between the manufacturer and the retailer under channel’s max profit. If the mechanism can guarantee channel’s max profit but can’t assure win-win, then the contract will not be acceptable, because it may hurt one of the channel in the supply chain.