初盛唐文学观念属于盛世的文学观念，以《易传》人文化成及《诗经》雅颂传统为基础，强调文章润色鸿业、颂美盛世的功能；中唐以后，盛世不再，盛世的文学观失去现实的基础，取而代之的是中兴的文学观念，立基于《诗经》之美刺传统及《春秋》的褒贬观念，强调文章在重建理想秩序中，改善政治、改良道德的作用。以文章改造社会乃中唐文士的共识，元、白与韩、柳为中唐诗、文代表，文学史研究者往往视之为两种文学思潮，分而论之，但元、白重建诗学，强调《诗经》之美刺；韩、柳提倡古文，发挥《春秋》之褒贬，其说虽异，精神实同。古文家一变《春秋》经 “遵周公之遗制” 的诠释传统，直以褒贬精神作文，表现出显明的史家意识；诗人则以史家直言、实录精神改造诗歌 “主文谲谏” 的传统，并以诗兼史传之功能，欲以诗歌传史，亦体现出浓厚的史学意识。文章观念的变化带来文学主题的新变，在美刺褒贬的文章观念下，一方面是中唐讽谏之文的大兴，另一方面是对小言片善的褒扬。中唐诗文突出底层士庶的善言善行，正欲借由这些 “小人物” 的事迹发挥文章的劝善功能，达到重建道德、革新政治之目的。

The literary concept of the early and high Tang belongs to the idea of prosperous age. Basing on the tradition of Yi Chuan and The Book of Songs, the literary function to polish the great achievement of the empire was emphasized. After the mid-Tang Dynasty, such a literary idea lost its basis of reality, and was replaced by the concept of renewal. Basing on the idea of praise and blame from the tradition of The Book of Songs and Springs and Autumns Annals, the literary function to improve politics and morality was underlined. Yuan, Bai and Han and Liu are the representatives of poetry and literature in the Mid Tang Dynasty. Literary historians often regard them as two literary trends and discuss them separately. However, Yuan and Bai reconstructed poetics and emphasized the literary function of critical assessments from the tradition of The Book of Songs; Han and Liu advocated ancient prose and giving full play to the function of praise and blame form the tradition of Springs and Autumns Annals. Although their words are different, the spirit is the same, demonstrating a clear historical sense. Changes in the literary idea have brought new literary themes. On the one hand, there is the great rise of satirical texts in the mid-Tang Dynasty, and on the other hand, literati highlighted the good words and benevolent deeds of the lower classes to achieve the purpose of rebuilding morality and reforming politics.