The purpose of this study was to 1) build a web-based instructional performance support system (WIPSS) for supporting teachers’ work, 2) to propose the functional framework, system design approach and model of the WPSS for educational use. The methodologies of ISD, PCD,and software prototyping was integrated to design and develop the EPSS system in this research. The system has been developed as well as completedαandβtest. The research is now undertaking summative evaluation including user and expert evaluations. Next step will be considering a experimentl study of long period to explore the effects and problems of system implementation.