Abstract: In the methods of current requirements prioritization, the user requirements are compared and prioritized at the same level, and the hierarchy of requirements is little considered. In this paper, a method of prioritizing requirements based on the combination of ISM and AHP is proposed, called Structural Analytical Hierarchy Process（SAHP）. The hierarchical model of software requirements is built with ISM. The requirements of top level of the model are prioritized by Analytical Hierarchy Process. The case analysis is given, and the strengths and weaknesses of AHP and the method are compared. The results show that this method is better than AHP as a whole, and can improve the rationality of the prioritizing requirements, and reduce the failure probability of the project.

Key words: software requirement, requirement priority, Interpretative Structural Model（ISM） technology, Analytical Hierarchy Process（AHP） method, requirement patterns

摘要： 针对当前需求优先级排序方法中，将用户需求放在同一层次上进行比较，设定优先级，而对需求层次性考虑得不多。从系统的整体性和需求的层次性出发，提出以解释结构模型和层次分析法相结合的需求优先级排序方法，其中用解释结构模型对需求进行结构分析和分层处理，对最上层的需求使用层次分析法进行需求优先级排序，将该方法命名为SAHP。在案例分析中，借助需求模式，对推广后的案例进行优先级排序，来说明该方法具有很好的通用性，给出案例分析和与AHP进行了比较。结果表明性能总体上好于AHP方法，该方法能够提高需求优先级设定的合理性，降低因需求导致项目失败的风险。

关键词: 软件需求, 需求优先级, 解释结构模型（ISM）技术, 层次分析（AHP）方法, 需求模式