Abstract: Software rectuirement modeling has a great effect on software rectuirements engineering. This paper offered a new theory of software requirements modeling based on the combination of software features, to improve the efficiency and quality of software requirements modeling process. To be started, software features were classified into functional features and non-functional features. Secondly,we made a formal definition of all the feature components in these functional features, including atomic and composite functional features.Thirdly, to support the formalization process, the fcature combination process of functional features was abstracted as feature operations, and we proposed 23 operation axioms. Then a formal definition of non-functional features was brought up, also a scope analysis was built to integrate functional and nonfunctional features as the ultimate software requirement model. At the end of this paper, a detailed software requirement modeling process was proposed based on the concept of software feature combination, which is also the innovation of this paper.

Key words: Requirement cnginecring,Feature,Functional fcature,Non-functional fcature,Fcature combination