This article reviews the literature in the field of vocabulary assessment especially that since the 1990s.Starting from the construct of vocabulary,which includes definitions of word and lexical item,and the connotations of knowing a word,it then reviews mainstream methods for the assessment of vocabulary,featured by the studies in the testing of vocabulary breadth and depth.After pointing out the problems and issues in the assessment of vocabulary,it proposes some suggestions which intend to shed some light to the future development of vocabulary testing.