Post-structuralist theories of language have become increasingly attractive to language learning researchers both domes?tic and abroad in recent years. As one of the primary conceptual frameworks informing language research, post-structuralism pro?vides new perspectives that expand the scope and relevant elements of language study far beyond other views. Then, what exactly is a post-structuralism perspective of language? What are its advantages and significance and how did language researchers apply it to language study? For an in-depth discussion of these questions, the paper first reviews the proposal of post-structuralist theories of language on the basis of a systematic comparison with structuralism, and explains its core ideas. Then, connecting theory with practice, we discuss the application of this theory to diverse language researches, identity issues in particular. Finally, attempts are made to put forward future research directions according to domestic research status, with the aim of offering some humble sugges?tions to future research on language learning in China.