【Objective】 Castanopsis grandicicatricata N. H. Xia & D. H. Vuong, a newly recorded species of Castanopsis (Fagaceae) from China is reported. This species is originally endemic to central and northern Vietnam, but now a scattered population is discovered in the Dawei Mountain area of Pingbian Miao Autonomous County, Yunnan. The study aims to verify the close relatives of the original literature based on morphological speculation, show the systematic status of this species, and increase the richness of Castanopsis plants in China. 【Methods】 The morphology-based speculation on the close relatives mentioned in the original literature was validated through phylogenetic tree reconstructions using nucleus ITS2 of rRNA gene 5.8S, 26S spacer and chloroplast rbcL molecular markers. 【Results】Morphologically, it can be distinguished from other known Castanopsis species by its cupule 4.5-6.0 cm in diameter, spine base connate into tree-like branched bundles, nut oblate, scar covering ca. 2/3 of the nut. 【Conclusion】 The results confirmed that C. mekongensis is indeed one of its close relatives, consistent with the morphological speculation; however, the overall phylogenetic framework of the genus is not clear. This new record holds significant implications for studying the flora of southeast Yunnan and northern Vietnam.