By the currently developed component models and standards, the component interfaces convey only limited semantics and the interaction protocol among components is hidden within the implementations, which may result in the problem of architectural mismatches, also make these components in difficulty to reuse, validate and manage. In this paper, an XML-message based architecture description language (XADL) is outlined, which supports the description of explicit interaction protocols and the composing relations of components. Based on the XADL, the notion of architectural mismatch is introduced and shows how it can be checked. The XADL enhances the descriptive capacity of interfaces, prevents systems from potential architectural mismatches, and facilities the implementation of system monitor, performance analysis and dynamic tuning.