Abstract: Web service composition makes it possible for Web service reused, assembled and providing value-added service .It is important to propose a complete,validate architecture for development and research of Web service composition. A Web service composition architecture based on the life cycle was proposed. The architecture supports process modeling, composition and execution. At the phase of modeling a GUI tool was provided to define the process which then was parsed by document parser to be stored in the service storage. In the composition phase services matcher based on ontology was introduced to solve service heterogeneous problem, and QoS of composite service was also considered.In the execution phase process monitor, exception handler and transaction adapter were provided.

Key words: Web service composition, Life cycle, Architecture, QoS