元语言意识是对语言结构有意识的觉察和运用。本文首先介绍 了什么是元语言意识及元语言意识测量的方法，接着讨论了元语言意识在母语和第二语言间的迁移，然后重点论证了元语言意识在第二语言 习得中的重要作用，最后提出了元语言意识在第二语言习得中的动态、交互作用模型，即元语言意识、母语、工作记忆和情感态度等影响第二语言习得的因素，构成一个动态有机的系统，它们共同影响第二语言的习得。

 Metalinguistic awareness is defined as the ability to reflect on and manipulate the structural features of language． The present paper first introduces the operational definition and the measuring tools of  metalinguistic awareness ，and talks about the transfer of  metalinguistic awareness  across  the  native  language  and  the  second  language． Then ，the  significance  of  metalin- guistic awareness in second language acquisition is justified．     Dynamic and Interactive Model is proposed at the end of the paper ， which depicts the exact influence of metalinguistic awareness in second language acquisition．        In this model ，metalinguistic aware- ness ，native language ，working memory ，naming speed ，and affective factors constitute a dynamic and organic system ，shedding influence on second language acquisition as a whole．