This paper focuses on the adverb Xu in Chinese as the research object to examine the semantic characteristics of the adverb Xu from a synchronic perspective, and explores issues such as its pragmatic function and semantic construal mechanisms. Firstly, from a synchronic perspective, it summarizes the semantic polysemy of the adverb Xu in Chinese and reveals its implicit negation-related attributes, such as the negated object, semantic features, and negation scope. Then, it analyzes the expectational negative function brought by the implicit negation semantics of the adverb Xu. Finally, extracts the speaker's intentions reflected in the usage of expectational negative adverbs in the process of discourse communication from a large amount of natural language data. The study finds that the adverb Xu has implicit negation semantics and possesses the expectational negative function shared by both the speaker and the listener. This expectation refers to the suitability conditions that both parties believe should exist but are lacking for the proposition to hold true. The negation of expectation reflects various subjective intentions of the speaker, such as believing that VP should not happen or VP should have real content, and embodies an ultimate humanistic concern through empathy with the listener's perspective.