Abstract [Objective] During a survey of forest germplasm resources in the Yangjifeng National Nature Reserve in northeastern Jiangxi, China, in 2021, the authors discovered a plant belonging to the Crassulaceae family and Sedum L. genus. This species differed from previously reported plants of the same genus, and this paper discusses and determines its taxonomic status. [Methods] Multiple populations in Yangjifeng were tracked, and detailed observations and morphological comparisons were conducted at different phenological stages to distinguish commonalities and unique traits. Additionally, its national distribution was determined through literature review and specimen examination. [Results] The species had a lotus-shaped nutritive branch in the seedling stage, which was most similar to Sedum subtile Miq. Distinguishing features included well-developed and trinodal sterile branches, 5 to 16 flowers per branch on the flower stem, and spatulate-lanceolate bracts in the former, while the latter had slender sterile branches with alternate or opposite leaves, 3 to 5 flowers per branch on the flower stem, and linear bracts. [Conclusion] The study indicated that this was a new species, and was named Sedum fluviale B. Chen & Z. W. Zhu. It was specifically found in stream environments and had a broad distribution, including provinces such as Jiangxi, Zhejiang, Fujian, Anhui, Hunan, and Guizhou. There had been numerous instances of misidentifications in the past. The holotype specimen was stored at the Shanghai Chenshan Herbarium (CSH).