The ternary world theory has been widely concerned by scholars from multiple fields such as computer science, information science, philosophy, and urban planning. However, its conceptual connotation, logical relationship, and division basis are still not clear enough. Based on the systematical analysis of related research results, this study endeavors to reinterpret the connotation, internal logical composition of the ternary world theory, and its relations with the Digital Twins and Metaverse, and form a new understanding of the Cyber-Physical-Social ternary world. Meanwhile, we focus on the practical application of the Cyber-Physical-Social ternary world theory in national security intelligence. By analyzing their internal relationship, we explore new scenarios and new methods in national security intelligence work from the perspective of Cyber-Physical-Social ternary world. This research is beneficial for recognizing the theory and application of Cyber-Physical-Social ternary world and has certain theoretical guiding value to the national security intelligence work.