Abstract: In order to solve the problems of fragmentation of knowledge and lack of semantic relationship in digital network courses，to deepen the control unit of knowledge to the level of knowledge element，the finegrained curriculum knowledge element organization model is constructed in combination with CELTS standard．And then use the theory of fine processing to arrange and design the teaching content，and define the logical relationship among knowledge element，knowledge chain and knowledge unit． The knowledge graph of C course is constructed to visualize the granularity of knowledge elements and the relationship between knowledge elements through Neo4j． Practice shows that the combination of knowledge elements and knowledge graph can effectively represent the logical relationship between knowledge and improve the correlation between knowledge．

Key words: knowledge organization, knowledge element granularity, knowledge chain, knowledge graph, CELTS standard