鑒於二十一世紀「紅學」研究，應立足於「文獻、文本、文化」三者的融通和雙向交流。本文擬從小說學角度，由探論《紅樓夢》風流公案與次文類（公案小說）的關連性爲起點。試結合「紅學」領域文化研究與文學性考察，嘗試貫通內、外部研究。本文的論述結構，先說明《紅樓夢》與「公案」的關連性，對照公案小說常見的敘事傳統及情節程式；其次，分析「風流公案」的敘事結構及其透顯的主題意涵。最後，從「次文類」的視角，檢視其小說美學乃至評估其藝術成就。研究發現，《紅樓夢》藉由「風流公案」，修正並綜合公案小說與才子佳人小說的敘事結構；又藉著「風流」的雙重意旨，涵攝「風月筆墨」，超越狹邪文類的純感官描寫。雖然，《紅樓夢》從傳統敘事中自闢新局，但以悲劇終篇，對所有通俗作品大團圓結局提出反叛。《紅樓夢》吸納融冶次文類於一書之中，成功地突破「期待的視野」(horizon of expectation)，見證經典「創新」的價值。

In view of 'Redology' (紅學) research in the 21st century, we should base on the integration and two-way exchange of the 'document (文獻), text (文本), culture (文化) '. This paper talks about "Dream of the Red Chamber" (《紅樓夢》) by connecting 'fengliugongan' (風流公案) with 'Dectective story' (公案小說). I try to blend the cultural research and literature investigation of 'Redology'. The structure of this essay contains for three main parts: First, I explain the correlation between 'Gongan' and "Dream of the Red Chamber", and analyze the narrative tradition and plot-formula in 'Dectective story' and in "Dream of the Red Chamber"; Secondly, I analyze the narration structure and its feature of 'fengliugongan'. Finally, from the approach of the 'subgenre', I inspect aesthetics and assess artistic achievement. I discover that, "Dream of the Red Chamber" revises the narration structure of the 'Dectective story' and 'Romance of young talent and beauty' (才子佳人小說). And "Dream of the Red Chamber" go beyond the sensation of 'Courtesan novel' (狹邪小說). On the other hand, "Dream of the Red Chamber" revolts to all popular novel by ending as a tragedy. In a word, the tragedy broadens 'horizon of expectation' (期待的視野) successfully and witnesses the vaule of innovation.