明中葉羅欽順提出「理氣為一物」、「理為氣之理」以解決朱子理先氣後說留下之問題。羅氏之理氣一元論的觀點，雖出自對朱子之補充或修正，但其理論效果是否全合於朱子之既定範圍，則有深入檢討之必要。 本文從理概念之地位、理與欲及天命與氣質之性的統一、太極與陰陽二氣之關係，三方面探討「理氣為一物」時可能的思考方向與新的觀點。羅欽順以發揚朱子為己志，其理氣一元論之理論效果，雖有同於朱子處，但也有超出朱子理氣心性論之趨向。羅氏學問之性質及其評價，迄今仍見仁見智，本文或可作為此問題之參考。

　　　　　In Lo Ch'in-shun's 羅欽順 thesis "The Unity of Li and Ch'i," Lo postulated that according to Chu His 朱熹 li 理 is nothing but the principle of ch'i 氣. His explanation of this monism resulted in the rising of new approaches to Chu His's old doctrine. This paper analyzes Lo's concepts, such as his concept of li, the unity of the principles of Heaven and the desires of human nature, the unity of the secular and spiritual worlds, and the relationship between t'ai-chi 太極 and yinyang 陰陽. We find that Lo's monistic li and ch'i brought a different understanding of these principles to li studies (理學). As a result, Lo was regarded as a materialist. Although it is still nearly impossible to evaluate all of Lo's achievements, hopefully this paper will provide some deeper insight into Lo's thinking to provide innovative ideas for further study.