The language system of the second language learners embodies learners’ language identity,cultural identity and ethnic identity,and to a certain extent the identity restricts the development of the second language ability.In recent years,more and more scholars have realized the important role of identity in second language learning,so identity research has become a new hotspot in the field of second language learning.Based on the analysis of the connotation of language identity,cultural identity and ethnic identity,this paper explains in detail the new understanding of second language learners’ identity,sorts out carefully the influence of identity on second language learning,and systematically discerns different factors influencing the development of identity.Meanwhile,this paper discusses the theoretical framework of the existing identity research,puts forward the teaching strategy of enhancing the identity from the perspective of teachers,teaching materials and teaching methods,and finally proposes the development direction of the second language identity research.The purpose of this paper is to provide a theoretical support for aiding Chinese learners to construct positive identity in classroom teaching through the review of the latest research progress in the field of second language learning.