Abstract: Based on semantic grammar and construction grammar, the paper comprehensively examines the core semantics and semantic modality levels of the construction of ji X you fei Y (both X and non-X) both from micro components and macro events. It also explores the motivation and mechanism behind the construction. Firstly, the components of the construction are analyzed. The predicate characteristics of the variable components are obvious and often present a relatively contradictory relationship. Following the analysis of the components, the study further investigates the semantic types of X and fei X (non-X) to derive the core meaning of the construction. Subsequently, based on the investigation of the semantic types of X and fei X, the core meaning is revealed. Namely, it highlights the observer’s contradictory and complex psychological perception of people, things and abstract concepts. Therefore, subjective judgment is strongly presented. The semantic modality is described in detail both from self-oriented or external-oriented perspectives. Consequently, it is found that the construction demonstrates strong informational sufficiency and common ground. Finally, from the perspective of pragmatic motivation and cognitive mechanism, the paper analyzes the reasons for the reconciliation of the contradictions represented by the construction.