Abstract: Soil organic carbon stock is the main part of organic carbon stock in terrestrial ecosystems， may have important effects on the global carbon cycle and global warming. In this study， by field sampling and laboratory analysis， the soil profile is divided into six layers: 0-10 cm， 10-20 cm， 20-30 cm， 30-40 cm， 40-50 cm， 50-100 cm. Comprehensive analysis of the distribution characteristics of the soil organic carbon density on the Altai Mountains’ southern slope. The results showed as follows： （1） In this region， soil organic carbon densities have vertically distributing regional characteristics， and organic carbon densities of different soil types are as follows: Brown calcic soil（11.29 ±1.66）kg·m ^-2 ， mountain brown calcic soil（16.02±2.74）kg·m ^-2 ， mountain chestnut soil（26.64±3.38）kg · m ^-2 ， mountain chernozem soil（65.79±8.92）kg · m ^-2 ， mountain gray coniferous forest soil（78.14±9.34）kg · m ^-2 ，mountain brown coniferous forest soil（74.48±4.03）kg · m ^-2 ， subalpine meadow soil（48.22±5.06）kg · m ^-2 ， alpine meadow soil（59.94±3.24）kg · m ^-2 ， and alpine frost soil（21.29±2.72）kg · m ^-2 . With the elevation increasing， from 500 to 2 400 m， soil organic carbon densities are gradually increased， from 2 400 to 3 000 m， are declined.（2）As far as 0-100 cm layer of soil profile， soil organic carbon densities are declined with soil depth increasing， and coefficients of variation of soil organic carbon densities are not exactly the same in different layers； soil organic carbon densities of each layer are significantly different for different soil types （p< 0.05） .（3）The soil organic carbon storage is 0.477 4 Pg， and different soil types’organic carbon storages have greatly varying （p＜0.05） . Sub-alpine meadow soils have the largest storage， followed by mountain gray coniferous forest soils； alpine cold permafrost and brown calcic soil have the least storage； 0.225 Pg being in the 0-30 cm layer， taking up 44.13% of the total storage. This study will provide the basic data of the organic carbon storage for the Altai Mountains region， and provide a reference about resource development and environmental protection at the same time.

Key words: Xinjiang, soil organic carbon density, vertical distribution, storage