In this paper, we evaluated the sources and spatial variations of inorganic carbon in the surface sediments of Lake Bosten and explored the influencing factors.The samples were collected at 13 sites in the main section of the Lake Bosten in August, 2012, using a Kajak gravity corer.The sampling sites covered most parts of the lake, with water depths from 3m to 14m.Total inorganic carbon(TIC), stable carbon and oxygen isotopic composition in carbonate(δ¹³C_carb & δ¹⁸O_carb) were analyzed.Our data showed that the contents of TIC ranged from 3.8% to 9.8%, with an average of 5.5%.The analysis of the stable carbon and oxygen isotope composition of carbonate from the surface sediments showed the values of δ¹³C_carb and δ¹⁸O_carb were from -0.23‰ to 2.27‰(0.71‰) and from -5.53‰ to -2.55‰(-4.4‰), respectively.According to the concentrations of lake water anion and cation and pH values, we calculated the saturation coefficient index with respect to calcite(IAP/Ksp), and the results showed that the lake water in Lake Bosten had a necessary condition of authigenic carbonate precipitation.Judging from the spatial distribution, TIC showed much higher values in the north area than in the south area, with the highest content occurring near the Huangshui area and lowest in the south estuary and central lake section.In general, the spatial distribution of TIC in the surface sediments of Lake Bosten was mainly under the influence of inflows by Kaidu River and Huangshui River, which resulted in the spatial differences of lake water salinity and nutrients, thereby affecting the precipitation and distribution of carbonate.In addition, lake hydrodynamic conditions might also affect the preservation and distribution of inorganic carbon in local environment of the Lake Bosten, especially in the mid-west lake section.The δ¹³C_carb and δ¹⁸O_carb values were significantly different in different lake environment, with the most negative values near the Kaidu River estuary and the east-deep water area.According to the correlation between δ¹³C_carb and δ¹⁸O_carb values, we inferred that the sedimentary carbonate was mainly formed in a closed basin.