Cybersecurity is a crucial component of national security strategy, receiving significant attention from countries worldwide. Cyberspace data is a typical example of big data, characterized by its diverse sources, various types, and large volume. Security incidents in cyberspace exhibit three main characteristics: large scale, evolvability, and correlativity. Addressing these characteristics to comprehensively, accurately, and in real-time assess cybersecurity incidents is a global challenge. Drawing on the human cognitive process for understanding cybersecurity incidents and based on a comprehensive analysis of existing cognitive models, this chapter introduces a new cognitive model in the cybersecurity field—the MDATA cognitive model. Additionally, it details the composition and operational principles of the MDATA cognitive model.