Interdisciplinary research has emerged as a prominent research method for solving complex problems. This paper provides a comprehensive analysis of advancements in interdisciplinary research, highlighting existing challenges and suggesting future research directions, making it a valuable resource for subsequent studies. First of all, this paper proposes a definition of interdisciplinary research that includes both interdisciplinary activities and their outcomes. It then systematically reviews current research through five key themes: definitional cognition, influencing factors, evolutionary processes, identification, measurement, and evaluation. The analysis reveals three major challenges facing interdisciplinary research: a lack of unity at the cognitive level, the necessity of achieving deeper knowledge mining in identification and measurement studies, and the need for an improved evaluation system and knowledge organization. In this regard, future research should concentrate on several key areas: understanding the mechanisms of interdisciplinary activities, developing identification and measurement methods for knowledge units, and designing multidimensional evaluation criteria while optimizing knowledge organization. Finally, this paper constructs a roadmap for interdisciplinary research at the level of knowledge units, aiming to provide new perspectives for future research.