词汇习得是第二语言学习的核心环节，而多义词的语义扩展与语法化演变是汉语词汇习得的主要难点。本文以认知语言学的概念隐喻、主观化、原型范畴理论为基础，以汉语高频词“看”的语法化路径为核心案例，结合“打”“开”“头”等多义词语料，分析汉语词汇语义扩展的认知机制，归纳学习者的习得层级与常见偏误。研究发现，汉语多义词语义演变遵循“具体动作→认知判断→情态标记”的认知连续统，学习者习得顺序与语法化路径高度重合。基于此，本文提出语义地图构建、隐喻意识激活、文化认知整合等可操作的习得策略，为对外汉语多义词教学提供具体的实践路径。

Vocabulary acquisition lies at the core of second language learning, and the semantic extension and grammaticalization evolution of polysemous words constitute a major difficulty in Chinese vocabulary acquisition. Grounded in core cognitive linguistic theories including conceptual metaphor, subjectification and prototype category, this paper takes the grammaticalization trajectory of the high-frequency Chinese word kan as the central case, and draws on corpus of other polysemous words such as da, kai and tou to analyze the cognitive mechanism of Chinese lexical semantic expansion, as well as to summarize learners' acquisition hierarchies and common errors. The study finds that the semantic evolution of Chinese polysemous words follows a cognitive continuum of "concrete action → cognitive judgment → modal marker", and learners' acquisition order is highly aligned with the grammaticalization path. On this basis, this paper proposes operable acquisition strategies including semantic map construction, metaphorical awareness activation and cultural cognitive integration, so as to provide practical approaches for polysemous word teaching in Teaching Chinese as a Second Language (TCSL).