Even today the design of Augmented Reality (AR) software applications is mainly guided by the available technologies and the targeted application. Indeed, the design remains ad hoc, which makes the reuse of such software difficult or even impossible to develop other AR applications. In this article we present a reconfigurable software architecture in order to improve flexibility and modularity of AR applications. It is a component based software architecture developed to meet the requirements of portability and variable component granularity. It also proposes several levels of abstraction separating the developers and enduser application designers.