Abstract: The Tang Dynasty is an extremely important period in Chinese history，and features of the vocabulary in this period will be revealed after indepth survey and comprehensive study.As there were not enough works like Dunhuang Bianwen to epitomize the spoken language in the early to middle period in Tang Dynasty，Tang Poems have become an important data source for studies on spoken vocabulary in Tang Dynasty.Bai Juyi′s poems retained a large number of spoken words，and were kept intact.Therefore they make a typical resources for the study of Tang poetries.This paper gives a general picture of researches on vocabulary in BaiJuyi′s poems by reviewing and evaluating the general situation and major achievements.

Key words: Bai Juyi′s poetry, Tang Poetry, vocabulary research, history of Chinese