歷來論杜者普遍以「沈鬱頓挫」代稱杜詩風格，清初吳瞻泰《杜詩提要》一書，則是明確以「沈鬱者，意也；頓挫者，法也。」來界定「沈鬱頓挫」的內容，並結合詩法、史法與文法的各種名目，運用評點的形式，對杜詩的章法結構作具體深入的分析，藉以探求杜詩「沈鬱」之意，避免膚詞讚美或穿鑿附會之弊。本文除了探討吳瞻泰所論的「頓挫」詩法外，吳瞻泰如何藉由「頓挫」的詩法來掌握杜詩「沈鬱」之意？「詩法」與「詩意」之間如何會通？是本文擬析論的重點所在。再者，倘若說詩「穿鑿」是連注杜名家都在所難免之病，吳瞻泰的說詩方式，何以較其他捨法而專言詩者，更能避免附會穿鑿之弊？其說詩又有何不足之處？透過吳瞻泰所揭示的「即法通意」、「按法詩得」的徑路，吾人不僅得以掌握杜詩的精髓、要義，亦可得見清初多元化的杜詩研究之一端。

Scholars of all the past generations generally identify the style of Du Fu’s poetry as chényù-dùncuò (profound and forceful). In the early Qing period, Zhan-Tai Wu‘s Preface to Du Fu’s Poetry defined chényù-dùncuò (profound and forceful) as “The meaning of the poem lies profoundly; so does the forceful prosody.” Furthermore, presentations of ideas in Du Fu’s poetry are concretely and deeply analyzed by combining different items such as poetics, grammar, and application of rating methods. By way of searching the meaning of chényù (profound), fraudulent practices of superficial compliments or strained interpretations and farfetched analogies are avoidable. This study does not only scrutinize Zhan-Tai Wu’s theory of dùncuò (forceful), but also how Zhan-Tai Wu applied it to figure out the meaning of chényù (profound) in Du Fu’s poetry. How to make a bridge between poetics and the meaning of the poem is the focus of analyses in this study. Moreover, on condition that even academics were unable to avoid these strained interpretations and farfetched analogies; then how did Zhan-Tai Wu prevent these fraudulent practices? Was there any flaw in the poetry? Through Wu’s revelation of understanding poetry by means of poetics, the substance of Du Fu’s poetry was no longer incomprehensible, but it has become perceivable that the research of Du Fu’s poetry of early Qing period possesses diverse aspects.