李長吉詩以其獨特風格，引起後世效法，形成「長吉體」，其中李義山的追摹最為明顯。李義山古體瓣香長吉，古今學者每有提及，但多是點到即止，全面而深入之專論則極少。對這論題之深入研究，不但可追溯義山的詩學資源，更有助於了解其詩歌獨特風格的形成。本文正是要釐清此問題：先從時局氛圍、心路歷程和藝術傾向三點，論述兩人相近之背景，如何促使義山對長吉詩風的接受和摹仿；繼而從體裁與韻律、章法結構、修辭手法三方面切入，通過對兩人詩歌的比較，具體分析義山的摹仿情形，及其如何在摹仿中有所開拓，發展出自己的特色。

The poems of Li He (李賀) arouse the future generations to follow because of the unique style; it forms the ＂Changji Style＂ (「長吉體」), of which the imitation of Li Shangyin (李商隱) is the most obvious. The archaic style poetry of Li Shangyin is a disciple of Li He, but ancient and modern scholars only mentioned it without the comprehensive and in-depth monograph. It not only can trace the poetics resources of Li Shangyin, and more help to understand the formation of his poetry style to deeply research this thesis. This article is to clarify this problem: first, from the political atmosphere at that time, the spiritual journey and the artistic tendency, discuss how their similar backgrounds prompted Li Shangyin to accept and imitate the poetic style of Li He; Then, compare their poems from the genre, rhythm, structural features and rhetorical device to make the concrete analysis of the imitation situation of Li Shangyin and how to develop his own characteristics in the imitation.