本文是對唐詩風格流變的探索之一，主要分析以韓愈、李賀為代表的中晚唐險怪詩風對傳統詩歌美學的背叛和創新。大曆詩人為這種背叛作好了理論上的準備和風格上的過渡；韓愈則以他那狠重的力度感和動態美、至險至怪的荒誕美、化醜為美和以醜為美，以及散體、折拗之美向傳統中和之美、自然之趣，以美襯美和美醜比襯，以及對稱、和諧的詩律結構發起挑戰；李賀則把這種新的美學觀念深入人的內心世界，或是以一種極濃的色調捕捉客觀世界的片斷，並概據自己的主觀意念作出重新組合或顛倒、變形的反映，或是根據自己的意識流動，若明若暗、朦朧恍惚地描繪夢幻中的世界，以此來反映自己曲折層深的內心。

　　　　　This is an exploration of change in Tang poetic style. The analysis focuses on the fact that in the mid-to-late Tang dynasty, the "Danger and Strangeness" poetry style, represented by Han Yu and Li He, rebelled against and brought forth new ideas from traditional poetic aesthetics. The poets of the Dali period had already completed the theoretical preparations and initiated the stylistic transition. Later, Han Yu issued a challenge to traditional poetics, so that features such as forceful and dynamic beauty, grotesque beauty, relativity and inter-equivalency of beauty and ugliness, and irregular beauty were opposed to traditional features such as the ugliness, as well as symmetrical, harmonious prosody. Then, Li He put this new aesthetic idea deep into people's minds. Sometimes, with intensely dark tones, he captured episodes of the objective world, and in the light of his own subjective thoughts, he recomposed, reversed, or deformed reflections; or on a stream of consciousness basis, he described a vague picture of a dream world, which refracted his deep inner world.