This paper proposes to represent software architectures with constraint hypergraphs, depict pre-and post-assertions of dynamic evolution of software architectures with left and right application conditions, and model the dynamic evolution process of software architectures with conditional hypergraph grammars. Firstly, how to construct conditional hypergraph grammars and how to apply to dynamic evolution of software architectures through a case study are discussed. Secondly, the consistency condition definition and the corresponding consistency decision method of dynamic evolution of software architectures are given out on this basis. Finally, an experiment is desisgned over analysis for dynamic evolution of software architectures to show the effectiveness of the proposed method.