Corpus linguistics has transformed linguistic research but has a slightly moderate impact on the ESL teaching and learning. The Wikipedia Corpus, designed by Mark Davis is introduced in this essay. The corpus allows teachers to search Wikipedia in a powerful way: they can search by word, phrase, part of speech, and synonyms. Teachers can also find collocates, and see re-sortable concordance lines for any word or phrase. The application of Wikipedia corpus is conducted in the experimental group whereas the conventional lexical teaching and learning mode with teacher imparting lexical information to students is carried out. The collected data is assessed and evaluated. The empirical evidence reveals the beneficial effects of corpus linguistics on ESL teaching and learning.