五言詩的詞彙較之四言詩有何變化？五言上二下三節奏引進了哪些四言體無法承載的新句式？這些新的句式如何拓寬「指事造形，窮情寫物」的範圍和開闢藝術構思的新途徑？新的藝術構思方式催生了什麼新的詩歌結構紋理，煥發出什麼新詩境？為了尋找這些問題的答案，筆者將借鑑傳統詩學和現代語言學理論，使用量化統計、溯源對比、審美細讀等方法，對早期五言詩代表作〈古詩十九首〉（下稱〈十九首〉）的詞彙、節奏、句法、結構紋理進行深入分析，力圖揭示各種不同詩境生成的獨特方式。同時，筆者還試圖將本文的分析結果與古人對〈十九首〉詩境的直觀描述相聯繫，使兩者互為闡釋，相得益彰，以求推動五言詩藝術的研究從「知其然」走向「知其所以然」，從而把傳統印象式評述提升為一種系統的理論闡釋。

This article seeks answers to a series of questions crucial to our understanding of Chinese pentasyllabic poetry. What new vocabulary dominates pentasyllabic poetry but is scarcely employed in earlier tetrasyllabic poetry? What new syntactic constructions coexist with the unique 2+3 rhythm of pentasyllabic poetry? How do these new syntactic constructions broaden the scope of external depiction and emotional expression? How do they enable a new mode of artistic creation and give rise to new poetic structures and textures? How do all these formal innovations help to bring forth new poetic visions? In addressing these questions, the author draws from both traditional Chinese poetics and modern linguistic theories in a broad array of critical ways (quantitative data analysis, comparative source studies, close reading, etc.) to study the ＂Nineteen Old Poems,＂ themost representative body of early pentasyllabic poetry. The analytical findings are presented along with the intuitive remarks made by traditional Chinese critics, in the hope of bringing the two into mutual illumination and elevating the studies from impressive criticism to systematic theoretical analysis.