Knowledge acquisition and analysis are especially vital works in the initial process of planning and design of land use. However, the knowledge of planning and design is multifarious and complicated, as all related references, rules, people’s opinions, expert’s suggestions are information that planners would care for.Therefore,this research aims to develop a framework that fits into some knowledge of planningand design as well as to design a system that planners and decision-makers can use sothat they can quickly search out the knowledge really needed. This research selects the planning of green open space of National Taiwan University as example.The key point of this research is Expert System, and rule-based model is used to organize all related knowledge. As a website is constructed to be User-Interface, users can easily use this system via Internet connection, and knowledge can be displayed with various types. The sources of knowledge are related professional books, theses, campus planning reports, conference records, surveying and expert interviews. This research uses CLIPS as a developing tool, and selects JESS to be the basis of User-Interface. Apart from statements, illustrations, tables and graphs, GIS (ArcGIS) and three-D visualization are added for support of knowledge representation. This research employs ASP.NET 2.0 to be the framework to develop the website, and ultimately to integrate all components for a Knowledge Management System for Planning and Design of Land Use.