This project plans to develop an open style software system for structural topology optimization by the employment of modern design methods and techniques for software engineering(for example object-oriented, plug-in technique, script language, UML), based on the software platform of computational mechanics- SiPESC. Main tasks are software design framework of optimization algorithms, software design framework of sensitivity analysis and filtering algorithms, open style software architecture, and high performance computational functions for large scale structural topology design problems. This project’s characteristics are open style system and integration capabilities for numerical algorithms and computational modules. The project’s aims are to propose general purposes software interfaces and management mechanism for dynamical extension, to implement and integrate typical numerical algorithms for structural topology optimization, and to realize high performance computation for large scale problem.