Abstract: In order to investigate the ecological adaptability of maize to root-zone soil salinity in Hetao Irrigation District, salt tolerance functions of maize was established based on the located observation in fields and the nonlinear least squares numerical approximation method. Meanwhile, the division standard of different ecological adaptable regions of the maize in Hetao Irrigation District based on the salt tolerance was proposed. The results showed that plastic film mulching in saline land had a good effect on salinity control in production, which reduced 61.2%、53.8% and 41.3% of 0-10、0-20 and 0-40 cm soil salinity in maize seedling, respectively and improved maize ecological adaptability to salinity. Both the piecewise linear response function and the nonlinear S-shaped functions could effectively present the relationship between maize relative yield and electrical conductivity of soil saturation extract. soil salinity in the layer 0-40cm was the most representative of root-zone salinity to maize salt tolerance analysis , and salinity tolerance index of Zhongyu 9 maize was 8.303. According to the salt tolerance, the farm land into the most suitable region, suitable region, sub-suitable region and unsuitable region were divided, where the salinity of 0 to 20cm soil layer out of plastic film in maize seedling respectively were below 1.178, 1.178 to 2.036, 2.036 to 3.465 and exceed 3.465 g/kg. This research can provide theoretical guidance for maize reasonable arrangement and efficient production.