Instructional planning is an essential professional activity often used by teachers. However, some characteristics of existing university-based teacher education programs may hamper pre-service teachers' learning of instructional planning. Thus, this study adopts the cognitive apprenticeship as a theoretical foundation to construct a web-based learning model that integrates expert teachers and Internet technologies (web-based multimedia, performance support system, and electronic conferencing). To examine the effectiveness of this model, a seven-week web-based course was designed and a field experiment was conducted. Experimental results reveal that the course based on the web-based cognitive apprenticeship model improves pre-service teachers' performance and attitudes on instructional planning more effectively than the traditional training course. Furthermore, the study discusses possible factors based on qualitative data and provides recommendations for future studies and web-based teacher education instruction. (Contains 3 figures and 2 tables.)