本文主要研究现代汉语当中“导师”一词作为直接称呼语的适用性问题。在研究中发现：“导师”在自然语言中主要承担间接引称和身份标识功能，极少用于直接称呼。其直接称呼的缺位，主要源于该词语义的庄重性、历史积淀的权威性，以及在现代汉语称呼语系统中“老师”一词的强势泛化。日常学术交流中，“姓+老师”是平衡礼貌与亲密度的最优策略，而“导师”的直接使用仅见于特定仪式化场合以表达高度敬意。本文为社会称谓语的分析提供了新的视角，对深化理解汉语称呼语系统及国际中文教育中的语用教学，具有参考意义。

This paper primarily examines the applicability of the term "导师" (mentor) as a direct address in Modern Chinese. The study reveals that "导师" primarily functions as an indirect reference and identity marker in natural language, rarely being used for direct address. The absence of direct address stems from the term's solemn connotation, its historically accumulated authority, and the strong generalization of "老师" (teacher) in the Modern Chinese address system. In daily academic communication, the strategy of "surname + 老师" represents the optimal balance between politeness and intimacy, while the direct use of "导师" is reserved for specific ritualized contexts to convey profound respect. This paper offers a novel perspective on the analysis of social address terms, providing reference value for deepening the understanding of the Chinese address system and pragmatic teaching in international Chinese education.