The content of Li Yu's ci can be roughly divided into two categories: the first category was written before the break of the country, mainly describing court life and love between men and women, and the subject matter was not extensive enough. The second was written after the country was broken. As the king of national subjugation, Li Yu's mood is self-evident. The works of this period are full of nostalgia for the past and rich emotions, and the literary achievements far exceed those of the past. Among them, the masterpiece is Yu Meiren Langtaosha's Scream of the Night. Bai Juyi divided his poems into four categories: satirical poems, leisurely poems, sentimental poems and miscellaneous poems. This classification comes from his Nine Books of the Imperial Garden, which is a letter that he entrusted Yuan Zhen to arrange poems for him.