The effects of aluminium sulphate (0, 300, 500, 900 and 1 400 kg/hm²) application on the rapid amelioration and fertility improvement of newly reclaimed soda saline-alkali paddy field were studied through a field experiment. Compared with the control treatment without aluminium sulphate, the pH value, total salt content, exchangeable sodium, cation exchange capacity, alkalinity, CO₃^2-, Ca²⁺, K⁺, Na⁺, water soluble organic carbon (C), aromatic C, carbonyl C, ratios of alkyl carbon/O-alkyl C and hydrophobic C/hydrophilic C, proportions of >2 mm water-stable aggregates and <0.053 mm silt plus clay fractions, and mean weight diameter of water-stable aggregates in soil generally declined, while SO₄^2-, (CO₃^2-+HCO₃^-)/(Cl^-+SO₄^2-) ratio, total organic C, humic acid C, fulvic acid C, humin C, organic C associated with various water-stable aggregate size fractions, alkyl C, O-alkyl C, aliphatic C/aromatic C ratio, proportions of 2~0.25 mm and 0.25~0.053 mm water-stable aggregates increased after the application of aluminium sulphate. The above effects were generally more obvious with the increase of aluminium sulphate application rates, but the differences between 900 and 1 400 kg/hm² application rates were generally not statistically significant. The above results suggested that the application of aluminium sulfate could decline soil alkalinity and salinity, increase soil organic C contents and improve its quality, which was thus an effective way for the rapid amelioration and fertility improvement of soda saline-alkali soil. However, it is noteworthy that the application of aluminium sulfate alone is not beneficial to the improvement of soil structure, and it is necessary to combine aluminium sulfate with other amelioration measures.