Abstract: Probability function is used to represent event randomness in risk analysis under uncertainty environments.As the generalization of probability function，belief function can model uncertain information in a more flexible way.Due to this reason，belief function is widely used in many application fields.In this paper，decision making based on belief function is studied.A numerical example in Theater Missile Defense（TMD） system is illustrated to show the use of the decision method based on belief function.

Key words: belief functions, decision making, evidence theory, risk

摘要： 不确定环境下的风险决策通常用概率函数来描述事件的随机性，作为概率函数的推广，信度函数比概率函数能够更好地描述不确定信息，所适用的范围更为广泛。在随机集的框架下研究了基于信度函数的决策方法，并将其应用到一个导弹防御系统中风险评估中。

关键词: 信度函数, 决策, 证据理论, 风险