Biomass, carbon concentration and carbon storage were investigated in the woody plants, herbaceous plants, litter and soil layers in a natural shrub ecosystem in Guiyang city, Guizhou Province. The results showed that biomass of the shrub vegetation was 23.16 t/hm², of which 12.46 t/hm² was in the woody plants (53.08% of the total biomass in the shrub vegetation), 3.74 t/hm² in the herbaceous plants (16.15% of the total biomass) and 6.96 t/hm² in the litter (30.05% of the total biomass). Carbon concentration ranged from 445.91 to 603.46 g/kg in 25 woody plant species, 408.48-523.04 g/kg in 6 herbaceous plant species, 341.01-392.81 g/kg in litter and 5.73-26.68 g/kg in the soils. The total carbon storage was 88.34 t/hm² in this natural shrub ecosystem, of which 9.17% was found in the vegetation (8.10 t/hm²), 2.89% in litter (2.56 t/hm²) and 87.94% in the soil components (77.68 t/hm²). The carbon storage in the shrub ecosystem decreased in an order soil component> vegetation component> litter component. Our results provide scientific basis and reference for estimating carbon storage and balance in urban forest ecosystems in the Karst areas.