Abstract: The relationship between bilingualism and cognitive development is an important problem in which psychologists are concerned. The review begins with the concept of bilingualism and introduces several classifications of bilingualism. Then the paper reviews researches on the relationship between bilingualism and cognitive development and the relation between bilingualism and metalinguistic awareness, evaluates the relevant interpretation theory and the inner mechanism of bilingualism advantage. Finally, the review evaluates previous research and raised some questions which need to be resolved in the future.

Key words: bilingualism, cognitive development, metalinguistic awareness