Abstract: In this paper，a new software behavior oriented requirements modeling methodology and a behavior description language （BDL） are presented.The design and realization of the requirements description language are discussed.By using the modeling methodology，effective behaviors of the target system can be extracted from the user’s requirements information，and then the behavior model of target system can be built.This modeling methodology can help the software users and developers to understand the behaviors of the target system more thoroughly，and can establish a foundation for automatically checking some characters of the target system.

Key words: requirements description language, software behavior, requirements engineering, modeling methodology

摘要： 提出了一种面向软件行为的需求建模方法和需求描述语言BDL，介绍了需求描述语言的设计和实现方法。利用此需求建模可以根据用户的需求信息寻找出目标系统的有效行为，建立目标系统的行为模型。该行为模型可以帮助用户和开发人员正确认识和理解目标系统的行为，而且能为以后自动检测系统的各种特性提供良好的基础。

关键词: 需求描述语言, 软件行为, 需求工程, 需求建模方法