Abstract Research on plant biodiversity and carbon stock estimation are highlighted due to global issue on climate change. Therefore, this study was conducted to record plant diversity and estimate carbon stock in Kuningan Botanical Garden (KBG). Nested plots 20m × 20m were placed systematically with random start sampling to record tree species and to estimate carbon stock. Poles were recorded in subplots 10m × 10m; shrubs and sapling in subplots 5m × 5m; while seedling and herbaceous plants in subplots 2m × 2m. Data were analyzed to calculate Shannon Wiener diversity index and important value index (IVI). Destructive method was used to estimate soil carbon content, meanwhile tree carbon content was estimated by using allometric method. Biodiversity index in KBG is 2.8 with dominant trees were S. wallichii (IVI: 46.22%) and Gmelina arborea (IVI: 30.24%); S. wallichii (IVI: 65.87%) and Gnetum gnemon (IVI: 39.11%) in pole stage; Adenanthera Pavonina (IV: 41.56%) and G. gnemon (IV: 41.56%) in seedling stage. Dominant shrubs were Mimosa invisa (IVI: 59.42%) and Mimosa pudica (IVI: 42.90%); Centrocema pubescens (IVI: 26.52%) and Paspalum cartilagineum (IVI: 25.91%) as dominant herb in KGB. Plant composition in this area depicted human activity (plantation) changed natural forest composition. Carbon stock in tree stands is 25.45 tonC/ha (11.06%); understorey is 11.29 tonC/ha (4.9%); litter is 6.32 tonC / ha (2.75 %); necromass is 0.17 tonC/ha (0.07%); and soil organic carbon is 186.85 tonC/ha (81.21%). Therefore, we can estimate that total carbon stock in Kuningan Botanical Garden (156.4 ha) is 35985 tons.