Abstract: Soil organic carbon is the main part of terrestrial carbon reservoir and important part of soil fertility.The spatial distribution and reserves of soil organic carbon are very important for studying soil carbon cycle.According to the data from the second soil survey, soil organic carbon reserves was estimated and its spatial distribution was analysed by using GIStechnique.The results showed that the total amount of soil organic carbon is about 17.52×10⁸t.The carbon density of laterite, lateritic red soil and red soil in Guangdong Province is 8.83, 10.31, 9.15 kg·m^-2, respectively;lower than the mean carbon density of China.The carbon density of yellow soil and rice soil is 12.08, 12.17 kg·m^-2, respectively; higher than the mean carbon density of china.Soil carbon density is about 10.44 kg·m^-2 in Guangdong.The spatial distribution characteristic of soil organic carbon density in Guangdong is that the carbon density in south Guangdong Province is higher than that in north Guangdong Province, in that soil organic carbon density in north and middle Guangdong Province is 5～10 kg·m^-2 and in east Guangdong Province is 10～15 kg·m^-2.Soil organic carbon density mostly vary among 5～15 kg·m^-2.

Key words: Guangdong, Soil organic reserves, Soil carbon density, GIS