Abstract:As the scale of the Internet continues to expand, more and more network security data are generated. These data are characterized by multi-source heterogeneity, missing data, noise, inconsistency, etc., which severely affect the quality of network security data. Knowl edge graphs possess characteristics such as data unification, interpretability, and fusion rea soning, which can effectively address these issues in network security data. This paper ana lyzed the development and current research status of knowledge graphs in the field of network security. It focused on knowledge graph construction techniques such as knowledge entity recognition, relationship extraction, and knowledge graph completion. From three aspects: intelligent penetration, public sentiment detection, and threat perception, it systematically summarized the current specific applications and provides directions for future research. In the field of cybersecurity, an effective knowledge graph technology system in cyberspace pro vides support for knowledge elements and intelligent reasoning to deal with adversarial at tacks and defense games in high-dynamic environments. It also serves as the foundation for advanced,continuous,andthreat-awarecyberspaceoperations.