Educational software for teachers is an important, yet usually ignored, link for integrating information technology into classroom instruction. This study builds a web-based teaching material design and development system. The process in the system is divided into four stages, analysis, design, development, and practice. Eight junior high school history teachers participated in the evaluation of the system. Through experts' reviews and content analyses of their instructional materials and interviews, we found that instructional materials produced using the system appear to be more coherent and systematic, provide deeper and broader information for learning, apply more adequate teaching strategies, and lessen the design and development load on teachers. (Contains 5 tables.)