在贝叶斯公式的基础上提出了期望后验概率的概念 ,并通过信息搜寻过程中决策的风险损失、期望风险损失的概念 ,给出了在面临信息不完全且信息搜寻需要费用的情况下 ,如何根据风险损失最小化原理来确定是否应继续进行信息的搜寻活动的序贯决策模型 .然后讨论了信息搜寻的两种情况 ,最后给出了一个实例来演示模型的应用 Based on the Bayesian formula, the concept of expectation posterior probability is put forward. Through the concept of loss of risk and expectation of loss of risk in the process of information searching, this paper presents the concept of expectation posterior probability in the case of incomplete information and the cost of information searching , How to determine the sequential decision-making model of whether the information search activity should be continued according to the principle of minimization of risk loss.Then the two cases of information search are discussed, and finally an example is given to demonstrate the application of the model