Based on the forest inventory data,the biomass,carbon density and carbon storage of arboreal forest in Qilianshan National Nature Reserve in Gansu Province were analyzed.The results showed that:(1)The average biomass and carbon density of arboreal forest were 127.67 Mg·hm-2 and 62.48 Mg C·hm-2;the total biomass and carbon storage were 2 3 36.53 × 104 Mg and 1 143.58 × 104 Mg C,respectively.(2)The biomass per unit area of Picea asperata and Sabina chinensis were 140.70 Mg·hm-2and 89.57 Mg·hm-2,seperatively;the carbon density was 68.94 Mg C·hm-2and 43.42 Mg C·hm-2;the forest carbon storage were 947.04 × 104 Mg C and 118.73 × 104 Mg C,accounting for 82.81%and 10.38%of the total forest carbon storage,respectively.The distribution area and carbon storage of other tree species groups was relatively narrow.The results of this study provide a basis and reference for evaluating the carbon cycle of forest ecosystem and reducing the uncertainty of regional carbon budget in Qilianshan.