In September 2010, iPhone 4 was out of stock after it was launched in China. At that time, “holding iPhone 4” was a fashion symbol and a great number of customers wanted to get it. Owning iPhone could bring customers psychological satisfaction, and many customers were disappointed because they could not get the mobile phone. Similar phenomenon can be seen in other fashion products including electronic products, clothing, etc.. With the rapid development of economy, people’s living standard and consumption level are becoming higher and higher. More and more customers’ purposes to buy some goods are not only to meet their basic physical needs but also to pursue their psychological satisfaction of owning these fashion products. These fashionpursuing customers will be disappointed when they can’t get the fashion product they want after the sale period. Strategic customers can choose either to purchase the product in the regular sale period at the full price or to wait to buy the product at a discount price. If they buy the product in the regular sale period, their desire of owning the fashion product can be fulfilled, but with a higher cost. Otherwise, if they choose to wait to buy the product at the discount price in the clearance period, they will face uncertainty in the availability of the product and their desire cannot be fulfilled. They will be disappointed if they fail to get the product after the clearance period. Generally, customers have a rational expectation on the economic outcomes when they make their decisions. But the real outcome is often inconsistent with the expectation because of uncertain environments. If the real outcome is below their expectation, disappointment will arise. Otherwise, elation will occur. The larger the gap between their expectation and the real outcome is, the stronger they will be disappointed or elated. This psychological disappointment or elation will make customers’ economic utility decrease or increase in economic activities. Kahneman and Tversky (1979) showed that people tend to be disappointment aversion. How do sellers make the decisions on sale price and order quantity to maximize their profits facing such disappointment averse customers? What is the impact of customers’ disappointment aversion on the strategic behavior? We shall study these problems.