This book constitutes the joint refereed proceedings of the 18th China Conference on Knowledge Graph and Semantic Computing and the 13th International Joint Conference on Knowledge Graphs, CCKS-IJCKG 2024, held in Chongqing, China, during September 20–22, 2024. The 30 full papers and 11 other papers presented in this volume were carefully reviewed and selected from 168 submissions. They are organized in the following topical sections: Knowledge representation and reasoning; Knowledge graph construction and knowledge integration; Graph database and knowledge management; Machine learning on graphs; Knowledge retrieval and information retrieval; Knowledge graph and large language model applications; Knowledge graph open resources; Poster and demo; Evaluations.