Aluminum sulfate improver has a good effect on reducing the pH of soda saline and alkaline soil and promoting soil colloidal condensation and organic carbon accumulation. In order to reveal the effect of aluminum sulfate improver on the carbon sequestration performance of soda saline-alkali soil under straw returning conditions, the adsorption performance of saline-alkaline soil on humic acid was studied after adding straw and aluminum sulfate and culturing for 300 days under constant temperature conditions. The results showed that in the adsorption kinetics of humic acid, under the different addition conditions of straw and aluminum sulfate, the adsorption of humic acid by saline-alkali soil reached the equilibrium of the quasi-second-order kinetic equation at 120 min, R². The highest value (0.936). Both the Langmuir equation and the Freundlich equation can better fit the isothermal adsorption of humic acid by saline-alkaline soil. Under the condition of adding the same proportion of corn stover, the maximum adsorption amount obtained by the Langmuir equation was 69.335, 42.830, 40.498 and 42.593 mg/g, respectively. Under the condition of adding the same proportion of aluminum sulfate improver, the maximum adsorption amounts were 21.358, 32.647, 69.335, 49.232, 62.375 and 42.830 mg/g, respectively.