Purposes: When making decisions, people usually make an affective forecasting of a special choice, which shows that affective forecasting has a great effect on decision making. Affective forecasting can be broken down into four components: predictions about the valence of one's future feelings, the specific emotions that will be experienced, the intensity of the emotions, and their duration. Previous studies found that people often got the valence of the emotion right, but were not as good at judging emotional intensity or duration. Typically people overestimate the intensity and duration, thus there are intensive bias and duration bias in affective forecasting. These biases can have serious consequences for the decisions people make, but they were devoid of research on the connection between affective forecasting bias and decision making. This study integrates the validation of intensive bias and duration bias in decision-making to explore the relationship between affective forecasting bias and decision-making. Methods and Procedures: Experimentation adopts the ultimatum game formulas and self-edit questionnaire to investigate 188 school students in Beijing. Each participant was assigned to the role of proposer and given a packet of materials. Instructions for proposers stated that the participant had been paired with another participant (the computer controlled person, named “Xiao Ming”), and that he or she should allocate ￥100 between himself or herself and Xiao Ming. There were 101 potential offers (in RMB Yuan units) ranging from ￥0 to ￥100. Proposers were told that responders could accept or reject the offer. If Xiao Ming accepted, the ￥100 would be divided accordingly, and if Xiao Ming rejected, both parties would receive nothing. As mentioned above, proposers completed four tasks. First, they rated their feelings of pleasure about their payoff (accepted/rejected). Responses were on a scale from 1 to 5, where 1 represented feeling extremely unhappy, 5 represented feeling extremely happy, and 3 represented feeling neither happy nor unhappy. Next, they were asked to attend the ultimatum game. Then they were told their payoff were accepted or rejected (the acceptance or rejection was randomly arranged, no integration with the offer of proposer), and rated their immediate feelings about the acceptance/rejection. Finally, ten minutes later, all participants rated their emotion about the acceptance/rejection, willingness of joining another ultimatum game, and attended the game again. Results and Conclusions: The result can help understand forecasting bias, promote decision-making ability, and improve decision-making quality. It shows that adolescents have intensity bias and duration bias when they predict the emotional response to future events. Intensity bias and duration bias influence adolescents to obviate the decision or tend toward it. On condition that the payoff was accepted, the higher the intensity bias, the more the adolescents avoid the decision. On condition that the bid was refused, the higher the intensity and duration bias, the more the adolescents tend to make a decision.