Summarized the results of carbon pool and carbon dioxide dynamics of the pristine ecosystem of tropical mountain rain forest at Jianfegling,Hainan Island.The results indicate that:(1) the carbon pool of the forest ecosystem consisted of three main parts with a total amount 342t/hm~2 (converting into carbon dioxide up to 1254t/hm~2),of which the forest biomass pool occupied 234.31t/hm~2,litter fall pool 2.98t/hm~2 and forest soil pool 104.696t/hm~2; (2) the basic dynamics of carbon dioxide in the forest ecos...