In the Chinese lexical system, idioms constitute a crucial component. The study of idioms is extensive and longstanding, yet it often adheres to conventional perspectives, lacking in substantive innovation. This paper focuses on the application of the “Spreading-Activation Theory Model in the Understanding of Metaphorical and Metonymic Idioms in Chinese”. Firstly, it clarifies the application and analysis of cognitive metaphor models in current idiom research, emphasizing three features of the source domain within idioms: (1) the relationship between the source and target domains, (2) the number of source domains within idioms, and (3) the inherent characteristics of the source domain. Drawing upon the Spreading-Activation Model, this study breaks free from existing theoretical frameworks, explores novel perspectives, and establishes a new classification system for metaphorical and metonymic idioms in Chinese. These idioms are classified into four categories: (1) Directional activation Idioms, (2) Cooperative activation Idioms, (3) Spreading activation Idioms, and (4) Superimposed activation Idioms. Through theoretical analysis, it derives a continuum of cognitive difficulty for these four idiom categories. This classification system broadens our understanding of idioms within ontological research, expands the typology of the Spreading-Activation Theory, and simultaneously contributes to idiom translation and teaching research.