Little attention has been paid to the process of mineralization of saline-alkali soils. Effects of litter addition and no addition on organic carbon mineralization in saline-alkali soil under different salinity and pH conditions under simulated natural state. The results showed that litter addition significantly (P<0.05) increased the cumulative mineralization of the 3 plots. Under the same salinity and pH conditions (except pH 10.5), the Alashan (ALS) plot has the highest cumulative mineralization among the 3 plots; under different conditions, there is no significant effect on the mineralization of the ALS plot; the Wulanchabu (WLCB) plot The mineralization amount was the highest at S9 and pH10.5, which were 2.23 g·kg^-1 and 1.84 g·kg^-1, respectively; the mineralization amount of the Eerduosi (ERDOS) plot decreased significantly with the gradient (P<0.05). The cumulative mineralization process fits the first-order kinetic model. Therefore, changes in salinity and pH conditions are not the most important factors affecting the cumulative mineralization of the 3 plots, but the physical and chemical properties of the soil itself and the chemical composition of litter have a closer influence on it.