The soil organic carbon density and storage of Maiji Area of Tianshui was estmiated using the data of6060 soil profile from the second soil survey of China and formulating fertilization for soil conditions in 2008.Integrating the soilmap, land use status map and district map of Maiji Area of Tianshui, the index of the characteristic of soil organic distribution in different soil and soil layers were analyzed.Results showed: the soil of Malji area have low average density, when soil secondary census, depths of 5cm,20cm, lm average density of organic carbon are 0.92kg·m-2,3.31kg·m-2,7.79kg·m-2 respectively, average density of organic carbon at depth of20cm is 2.43 kg· m-2 in 2008 years, As a standard of Yu Dongshengs (2005) estimation of average density of9.60 kg·m-2 in the depth of lm all over the China, Maiji area lm deep soil organic carbon density is lower1.91kg·m-2than the average density of whole country; The calculation of the secondary survey, reserves of organic carbon in surface soil (0-5cm) is about 4.83×106t, reserves of organic carbon in fall (0-20cm) is about12.46×106t, reserves of soil organic carbon in lm depth is about 45.17×106t, reserves of soil organic carbon in fall (0-20cm) is about 18.55×106t in 2008 years.In a word, the soil organic carbon storage was relatively indigent in Maiji Area of Tianshui.