As one of the fragile ecosystems, the biological species in desert area have obviously regional characteristics. The discharge of high salt oil production wastewater has certain influence on desert ecosystem. In this paper, the constructed wetland in Karamay oilfield as the research object, and 12 quadrangles were collected by equidistant distribution principle. The area of effected by constructed wetland and the area of background were separated by GeoDetector and cluster analysis. The physicochemical properties of soil, the plant diversity and their ecological risks of soil salinity in these two areas were assessed. The results showed that the drainage of oil production wastewater had great influence on the surrounding soil moisture content. The moisture content of the background site was below 6.5% while that of the wetland affected site was 12%-30%. The drainage of oil production wastewater has not significantly affected on the total soil salinity, and the soil salt content increased from northwest to southeast in the whole study area. There were 8 species in the whole study area, 4 of which were common species in the two regions, but there were significant differences in plant growth status between the two regions. The vegetation coverage varied widely in wetland affected areas, ranging from 1% to 40%, while that of the unaffected area was below 20%. In this ecosystem, the predicted no-effect concentration of salt was 83.04 g/kg through the toxicity effect analysis. Compared with the actual concentration, the risk entropy was less than 1, and the exposure of salt did not cause the ecological risk.