Cloud computing is a new software paradigm for resource integration and sharing in the open, dynamic and autonomous network environment. For large-scale complex software system on the dynamic evolution of the software architecture, taking service as the basic unit, the user can select service components and configuration online, can release of application form, and the ability to modify the published application. Current service dependencies including user application software architecture of logic dependency and dependency of evolution in the history of evolution, through the analysis and optimization of clustering in the service dependencies and reconstruction scheme of the user application software architecture is given.