【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 genus. This species differs from previously reported plants of the same genus, and this paper discusses and determines its taxonomic status. 【Methods】 Multiple populations on Yangjifeng were tracked, and detailed observations and morphological comparisons were conducted at different phenological stages to identify similar and distinguishing characteristics. Additionally, its national distribution was determined through literature review and specimen examination. 【Results】 The species has a lotus-shaped nutritive branch in the seedling stage, with the most similar species being Sedum subtile Miq. Distinguishing features include 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 has slender sterile branches with alternate or opposite leaves, 3 to 5 flowers per branch on the flower stem, and linear bracts. 【Conclusion】 The study indicates that this species is new to science and is named Sedum fluviale B. Chen & Z. W. Zhu. It is specifically found in stream environments and has a broad distribution, including provinces such as Jiangxi, Zhejiang, Fujian, Anhui, Hunan, and Guizhou. There were previously many misidentifications. The holotype specimen is stored at the Shanghai Chenshan Herbarium(CSH).