According to the characteristics of saline-alkali soil in the experimental area, the gypsum and humic acid used alone and combined to mitigate the negative effects of soil salinity on cotton growth. Soil salt content, pH, plant height, stem diameter and yield were measured during the cotton growth period in order to determine the optimal soil amendment for the test area. The results showed that 9∶1 of gypsum to humic acid with the application amount of 3 000 and 4 500 kg/hm² had the better desalination effect in 0–20 cm soil than those of gypsum and humic acid used alone. Humic acid used alone had the best effect on cotton yield, increased by 29.8% compared with CK (no amendment). In conclusion, the optimal soil amendment was gypsum combined with humic acid with a ratio of 9∶1 and with the application rate of 3 000 kg/hm², it could decrease salinity in 0-20 cm soil by 24.3% and increase cotton yield by 24% compared with CK.