Disposition Effect refers to the phenomenon that investors tend to sell profitable stocks and continue to hold loss stocks. It is typical irrational behavior. Simultaneously, due to the limited professional knowledge of individual investors and their investment behavior is greatly affected by emotions, the disposition effect is evident in the investment process. The disposition effect belongs to the category of behavioral finance. Based on prospect theory, this paper explains the behavior deviation of individual investors in the capital market from an irrational perspective. Through the research on it, it is helpful for investors to understand their irrational behavior and guide the development of investment theory and practice.