Aspect-Oriented Programming (AOP) can effectively solve the code-tangling and code-scattering which are caused by crosscutting attributes. However, much work is presented on the programming and the implementation phase, and few works have addressed the early model stages. This paper aims at applying AOP in the phrase of requirements engineering. On the requirements analysis phase, functional concerns and non-functional concerns are identified and separated. The core class and aspect class are modeled with class diagrams and state-chart diagrams in UML, and then the non-functional concerns of the system are weaved in a later phrase. Furthermore, this paper proposes a way to detect and resolve the mismatch among the aspects. Keywords: AOP; UML; Requirements Engineering; Mismatch