Abstract:Organic carbon in citrus ecology was detected by the field investigation and measurement in Yongchun County, Fujian Province. The results showed that citrus organs had a positive correlation with each other based on analyzing of biomass linear regression model. Correlation coefficient of stem, leaf and fruit both exceeded 0.90. The correlation coefficient between height and base diameter was 0.893333. The carbon density in the ecosystem was 222.796 t?hm-2,in which soil(0-100 cm)carbon density was 200.214 t?hm-2,vegetation carbon density was of 22.582 t?hm-2,account for 89.864% and 10.136% of total carbon density, respectively. From 1952 to 2007, the organic carbon storage in citrus ecosystem was increased from 445.592t to 2.205×106t in Yongchun County, which playing a role of sink.