In the Yellow River Delta, the normalized difference vegetation index (NDVI) was extracted from remote sensing images, whereas environmental data (e.g., topographic height, groundwater table, surface soil Cl ^- content, and others) were collected using quadrat sampling. To understand the relationships between the spatial distribution of vegetation and environmental factors in the study area, detrended correspondence analysis (DCA) and detrended canonical correspondence analysis (DCCA) were conducted. In addition, single factor correlation analysis and multiple stepwise regression analysis were also conducted using the regional NDVI and environmental factors. Results showed that the vegetation in the Yellow River Delta could be divided into four main community types: Suaeda heteroptera, Tamarix chinensis and S. heteroptera, Phragmites australis and T. chinensis, and P. australis. DCCA and DCA ordination diagrams were similar. However, compared with DCA, DCCA clearly showed that the first axis was mainly representative of Cl^- concentration in the phreatic aquifer and key water and salt factors. With the decrease in the salinity of the groundwater and soil environmental systems, the community evolved from S. heteroptera to P. australis. The distribution of the vegetation communities and NDVI in the area were influenced by the depth of groundwater table and Cl^- concentration in the phreatic aquifer. A binary regression relationship (R² = 0.57) was found between NDVI and two environmental variables. The effect of the soil Cl^- content on vegetation was influenced by the depth of the groundwater table and the Cl^- concentration in the phreatic aquifer. Because of the shallowness of the groundwater, groundwater was sensitive to vegetation growth and distribution. The groundwater table and Cl^- concentration in the phreatic water were the two key influencing factors on groundwater. In particular, the Cl^- concentration in the phreatic water largely controlled vegetation distribution and growth. To maintain wetland ecosystem health, the relevant departments should pay attention to the increase in groundwater Cl^- concentration caused by dried-up river courses, seawater intrusion, and shoreline erosion, among other factors, which will adversely affect vegetation. Some measures could help to accelerate the sustainable development of coastal wetland vegetation, such as making full use of the ecological regulations in the lower reaches of the Yellow River.