Abstract: Coastal wetlands are one of the most biodiverse ecosystems. Studying wetland plant diversity is important for maintaining the integrity and stability of wetland ecosystems. To provide a basis for the scientific management of the coastal wetland ecosystem, this study used the Caofeidian Wetland and Bird Provincial Nature Reserve as the research area, adopted the ecological sampling survey method, and selected sample plots with typical plant communities along the river bank, coast, and the direction perpendicular to the river bank and the coast, to investigate the spatial distribution of plant diversity, soil physical and chemical properties, and calculated the correlation between the two. The results showed that: 1) there were 23 families, 47 genera, and 54 species of seed plants in the study area. Angiosperms were dominant, and most of the plant species were mesophytic herbs. 2) The results of the quantitative structural analysis of the flora showed that there were four dominant families in the study area, namely Asteraceae, Poaceae, Chenopodiaceae and Fabaceae, and three representative families, namely, Chenopodiaceae, Plumbaginaceae, and Salicaceae. There were five dominant genera: Chenopodium, Lactuca, Suaeda, Artemisia, and Limonium, and the characteristic genera were Lactuca and Suaeda. The quantitative structure featured diversity at the family and genus levels. The geographical components of the flora were relatively complex, mainly in temperate and tropical zones. 3) The plant communities in the study area were mainly herbaceous, including nine vegetation communities: Suaeda salsa, Bassia scoparia, Artemisia annua, Suaeda glauca, Phragmites australis, Humulus scandens, Carex phacota, Bidens pilosa, and Artemisia capillaris, among which the communities of A. capillaris and H. scandens were most stable, and the diversity of P. australis community was the lowest. 4) The high-value areas of soil salt and available potassium were mainly distributed in the southwest of the study area, those of soil available phosphorus were mainly distributed in the northwest, and those of available nitrogen and organic matter content were relatively scattered. 5) The wetland plant diversity indexes were negatively correlated with soil salinity and positively correlated with soil nutrients, especially available nitrogen. The results of this study clarified the distribution and diversity of plants in the area and preliminarily analyzed soil impact factors. These results provide a scientific basis for the protection and management of plant diversity in the Caofeidian wetlands.