Based on the data of Beijing forest resources inventory,biodiversity and carbon storage of different forest ecosystem types in Beijing mountainous areas were evaluated by using InVEST（the integrated valuation of ecosystem services and tradeoffs tool）model.The relationship between them was also discussed.Results showed that the highest biodiversity was 0.76in natural birch,while the lowest one was 0.49in artificial Chinese pine.The total carbon storage of Beijing mountain area was 49 193 742t,with the highest one being 10 402 900tin artificial economic woodland and the smallest one being 423 132tin natural coniferous.The average carbon storage per unit area was relatively high in all of the forest types.In general,the carbon storage of one forest type is higher when the biodiversity is high.Biodiversity has a certain correlation with carbon storage,but the correlation is not very significant.