沈璟《增定南九宮曲譜》成書於萬曆年間，爲增補蔣孝《舊編南九宮譜》之作，在當時評價甚高，此譜集曲的收錄，更被認爲開創了後代曲譜以收錄集曲作爲曲調的新增來源。本文探討沈璟《增定南九宮曲譜》集曲收錄，從譜中收錄的189首集曲，探討沈璟增改《舊編南九宮譜》的情況，發現有以下四個重點： 1.以文字格律及音樂格式，判定集曲所犯曲牌。 2.判斷集曲的平仄正誤，以本調爲準，然實際創作與曲譜收錄多有出入。 3.對用韻及集曲宮調歸屬的看法。 4.對集曲俗唱與時人創作的訂正。由沈璟集曲的論述，可得知沈璟的集曲觀，以「本調」爲準，勘正當時集曲創作的觀念，對於後代曲譜及集曲創作方向產生了重要的影響。

Shen Jing's (1553-1610) book entitled Zengding nanjiugong qupu (Revised nanjiugong Formularies of Arias) was completed during the Wanli reign as a supplement to Jiang Xiao's Jiubian nanjiugong pu (Old Compilation of nanjiugong Formularies). It received a high evaluation at that time, and its collection of jiqu was considered predecessor to later assimilation of jiqu into tunes. This article looks into the collection of jiqu in Zengding nanjiugong qupu, through examining its added 189 pieces of jiqu it verifies how the author Shen Jing made amendments to Jiang Xiao's Jiubian nanjiugong pu. Four important points are found as follows: 1. To determine the tunes used in jiqu by examining word-sentence forms and music style. 2. To judge the accuracy of tunes in jiqu, basing on the original tune. Many differences are shown between the actual compositions and the collected jiqu. 3. Perspectives on the use of rhyme and the classification of the gong tune in jiqu. 4. The revision of jiqu folk singing and the rectification of compositions by Shen's contemporaries. With examination of Shen Jing's discourses on jiqu this article finds that, basing on "the original tune" Shen Jing rectified the contemporary perceptions of jiqu composition and made a great impact on the composition of formularies of arias as well as jiqu in later generations.