作为概率论的泛化，Dempster-Shafer证据理论基于上下区间的赋值概率被提出，它在信息融合，可靠性评估以及医疗诊断等领域应用广泛。对于D-S证据理论一个重要的应用是将基本信度指派(BBA, Basic Belief Assignment)，也叫做信度函数(Belief Function)转换成概率分布。在决策，分类，诊断等问题时，合理的转换更加有利于决策。本文基于量子基本信度指派(QBBA)的生成方法，构建了一种信度演化有向无环图(BEDAG, Belief Evolution Directed Acyclic Graph)，赋予了概率转换问题一个新的解释。在此基础上，将量子计算中的RY旋转门应用到BEDAG，提出了一种新的概率转换方法。根据概率信息容量 (PIC, Probability Information Content)这一指标验证，相比之前提出的经典方法，该方法的效果更优。

As a generalization of probability theory, Dempster-Shafer evidence theory (DSET) is proposed based on the assignment probability of upper and lower intervals. It is widely used in the fields of information fusion, reliability evaluation, and medical diagnosis. An important application of DSET is to transform the basic belief assignment (BBA), also known as the belief function into a probability distribution. In classification, diagnosis, and other issues, reasonable transformation is more conducive to decision-making. Based on the generation method of quantum basic belief assignment (QBBA), this paper constructs a belief evolution directed acyclic graph (BEDAG), which gives a new interpretation to the probability transformation. On this basis, the RY gate in quantum computing is applied to BEDAG, and a new probability transformation method is proposed. According to the indicator verification of probability information content (PIC), this method is more effective than the classical method proposed before.