Abstract: Aiming to characterize soil salinization, soil salinity profile types and distribution in the low plain around the Bohai Sea, soil samples were collected from 127 sites in the plain in this study. Soil samples in each site were taken from 0 cm to 60 cm in 5-cm or 10-cm increment, and soil salinity of each soil sample was analyzed based on the statistical method, principle component analysis method, hierarchical cluster analysis method and GIS technique. The results showed that the variations of soil salinity in the surface layer belonged to highly variation degree, soil salinity in other layers belonged to moderate variation degree in horizontal direction, while in the vertical direction, their differences are small. Soil salinity could be influenced by 5 principle components which were soil salinizaiton (principle component 1), soil alkalization (principle component 2), total regional dissolved soild, groundwater level (principle component 3, 5), source of kalium (principle component 4), and the cumulative contribution of these principle components added up to 87.88%. Hierarchical cluster analysis results indicated that salinity profile could be classified into 3 types, i.e. the top enrichment, the bottom enrichment and the middle enrichment. The percentage of each soil salinity profile type is almost equal, about 1/3. The top enrichment profile type is mostly distributed in the east coastal plain, the bottom enrichment profile type is mainly located in the inland low plain, while the middle enrichment profile type is distributed as map patches irregularly. Top enrichment profile type is the salinity accumulated state, on the contrary, the bottom enrichment profile is the desalinated state, while the middle enrichment profile type is the transitional sate between accumulation and desalination. The distributon patterns of salinity profile types reflected the effect of many factors to some extent.