Abstract: In order to solve the secondary saline-alkalization problems in the northwest arid areas of China, based on the laboratory experiment, soil water movement and salt transport in saline-alkali soil under different gypsum proportions were investigated. The results showed that the gypsum proportion had a great impact on the distribution of water in soil and the salt transport of saline-alkali soil was significantly influenced by it. With the increase of the horizontal and vertical advance distances of soil wetted front, the soil salinity also increased under different gypsum proportions. In the same infiltration distance, with the increase of gypsum proportion, the sodium content decreased while the sodium desalinization zone depth coefficient increased, which showed that the desalinization effect was distinct. When the gypsum proportion was 0.1, the increment of the sodium desalinization zone depth coefficient was greater than that of any other treatments. So the gypsum was propitious to wash soil surface salt under drip irrigation.