The paradigm of Component-Based Software Engineering aims to develop software by assembling and deploying reusable units, called software components. This approach tries to improve the flexibility, re-usability and maintainability of applications, and helps develop complex and distributed applications deployed on a wide range of platforms, by plugging commercial off-the-shelf components, rather than building them from scratch. In this context, the selection step is very important. It consists of searching and selecting appropriate software components from a set of candidate components in order to satisfy the developer-specific requirements. In the selection process, both functional and non-functional requirements are generally considered. In this study, the authors propose a method enabling quality evaluation of software component assembly. This method allows us to choose the best composition in term of quality.