Vocabulary is important in language and language acquisition, but it did not catch as much attention as it deserved for a long time. In this thesis, I’ll go through changes of vocabulary studied in linguistics and language teaching as well as rise of L2 vocabulary acquisition studies. Several aspects of L2 vocabulary acquisition studies will then be reviewed.Issues that need to be further studied will at last be put forward. Vocabulary is important in language and language acquisition, but it did not did catch as much attention as it deserved for a long time. I’ll go through changes of vocabulary studied in linguistics and language teaching as well as rise of L2 vocabulary acquisition studies. Several aspects of L2 vocabulary acquisition studies will then be reviewed. Thoughts that need to be further studied will at last last put forward.