Abstract: Synthesis design optimization environment was built for system integration, proc ess unification, parameter optimization and collaborative design. The high exten sible and multi-tiered architecture of this environment was built on the analysis of characteristic of complex engineering system. Four key modules were discussed: project organization and management module guarantees project schedul e and quality; process modeling and running module applies design task structure for representing design processes, workflow reference model for running, and pr ovides the ability of task transition across organization; design task unit base d on component technology integrates people, data and tool over network, and pro vides a coherent task model for system design; product data model uses PDM(prod uct data management) as information infrastructure, and provides a single repre sentation of product. The implementation of the environment and running mechanis m were presented. The prototype of this environment has been successfully tested by the design and optimization experimentations in fields of pneumatics, struct ure, control and system design.