To encode domain knowledge in reusable format, a large-scale and well-defined ontology is required for the Traditional Chinese Medicine discipline. In this study, we present an integrated approach for modeling and developing a large-scale domain ontology for the Traditional Chinese Medicine discipline. We propose to model the ontology based on an upper-level framework. Experts from different institutions work collaboratively to develop the ontology by following a certain procedure. A Web-based ontology editor was implemented for developing the ontology collaboratively. As a result, there are more than 10,000 classes and about 80,000 instances defined in the ontology now. The ontology has become large enough to cover the discipline and is used to support Traditional Chinese Medicine e-Science.