It is very significant for the medical and health enterprises to develop an efficient medical information grid to achieve sufficient medical data share and integration. In order to access heterogeneous data resources transparently, front agent is built on heterogeneous databases or medical systems, the same as the unified data models and mapping rules with grid services to communicate with upper grid middleware, so that users can query or access medical data conveniently. Two medical application instances, medical information integration and content-based image diagnosis or retrieval of emphysema disease, are introduced and realized with these technologies.