By research on Topic Map standard, the Extended Topic Map (ETM) is proposed as a novel model for better organization and management of the massive knowledge resources in E-learning. Based on the model, an Extended Topic Map Toolkit is designed and implemented, which supports exploration, search, consistency check and etc. The ETM Toolkit not only provides learners with visual navigation and search on massive E-learning resources, but also offers a way for instructors to collaboratively build the shareable and reusable domain knowledge efficiently. By ETM Toolkit, an extended topic map with a certain scale on Computer Networks has been built and is currently available for students in our university.