Many researchers in knowledge management point out that the first step toward knowledge management is the management of documents. However, the complexity imbedded in some documents could present great difficulty for most methodologies to deal with. The knowledge content for building an excellent quality management system that complies with ISO 9001 falls into this category; this knowledge is characterized by multi-dimensionality and knowledge embedment through various procedures and forms. We applied Ontology, which is a new approach in AI for better presenting knowledge structure of a domain, to develop a system structure that will facilitate the development of a knowledge-based ISO 9001 quality management system. We use the real case of a Taiwanese chemical company that has a total of 175 ISO manuals to refer to when needed. This system is built with Protégé 2000 as the knowledge platform, and we follow the development process recommended by Ontology Engineering of Toronto Virtual Enterprise. One main feature of the system is its capability of understanding the semantic of documents, which is a vital part of the inference mechanism in answering user's queries.