【Objective】Ca²⁺ produced by dissolution of desulfurized gypsum will react with carbon-containing anions (CO₃^2-, HCO₃^-) in the soil, and eventually CO₂ is absorbed and fixed as soil inorganic carbon. The inorganic carbon fixation of desulfurized gypsum in alkaline soil improvement is of great significance to achieving "carbon neutrality". 【Method】In this study, the 0-20 cm soil layer of desert alkaline soil in the Sangong River basin of Fukang, Xinjiang, was improved by using desulfurized gypsum as a calcium source. The changes in soil inorganic carbon (SIC) and soil inorganic carbon density (SICD) were investigated under different application rates of desulfurized gypsum at different times, so as to study the role of inorganic carbon sequestration in alkaline soil improvement. 【Result】The results showed that the application of desulfurized gypsum significantly reduced soil alkali damage (pH decreased) and increased soil salinity and inorganic carbon sequestration effect (SIC and SICD increased) (P<0.05). The optimal application rate of desulfurized gypsum was 30 t·hm^-2, when the pH of the improved soil layer was reduced to the lowest (8.24). The SIC increased by 0.93 g·kg^-1 and SICD increased by 0.29 kg·m^-2 (i.e., CO₂ fixation was 1.06 kg·m^-2) from 0 to 46 days after the improvement. The amount of desulfurized gypsum application was significantly positively correlated with SIC, SO₄^2- and Ca²⁺ (P<0.05) and negatively correlated with pH, CO₃^2-, HCO₃^- and Na⁺ (P<0.05) during the improvement process. Climatic factors had an effect on soil inorganic carbon sequestration; increasing relative humidity and precipitation suppressed the increase in SIC and SICD, while increasing wind speed, temperature and total solar radiation facilitated it. 【Conclusion】The results of this study provide direct evidence that the application of desulfurized gypsum to improve alkaline soils will increase the carbon sequestration potential of the soils.