Development based on software architecture is one of the most effective solutions to improve software qual-ity and productivity, and minimize the difficulties of developing large and complex systems. Formal models and speci-fications of software architecture are one of the key research areas of software architecture. In this paper, the exten-sion of XYZ/E Language based on set theory, called XYZ/E+ Language, is proposed, and a method of formalizingsoftware architecture whit it is formulated. The formal method is distinguished by its ability to represent not onlystatic properties but also dynamic behaviors, and its high-level abstraction and powerful expressiveness. Finally,through an example of formalizing software architecture of a specific system with XYZ/E+ Language, its powerfulmodeling ability and good practicality are demonstrated.
