Abstract: Salt content of soil potential safety-critical and the maximum potential capacity of salt in a case study area of low plain of Huan Bohai were analyzed in this paper, in order to provide a scientific basis for protecting soil safety and irrigating food crops with saline water safely. Salinity distribution of 0-40 cm deep soil was identified by field investigation and laboratory data analysis, and on the basis of which, the paper evaluated the potential safety margin of salt using factors of safety soil salinity for different salts, soil chemical type and crop distribution pattern. The results indicated that the soil potential safety salinity ranged from 1.0 to 3.0 g/kg in the low plains around the Bohai Sea. The area where the soil potential safety salt ranged from 2.0 to 2.5 g/kg accounted for 81.3% of the total area, indicating a great potential margin for salt content. The areas with salinity ranges of 1.5-2.0, 2.5-3.0 and 1.0-1.5 g/kg accounted for 10.0%, 5.4%and 3.1% respectively. For the maximum soil potential safety salinity, it ranged from 1.5 to 5.5 g/kg, which was dominated by the range of 2.5-3.5 g/kg, and the area falling in this range accounted for 68.7%, indicating a smaller salt tolerance. The area falling in the maximum soil potential safety salinity ranges of 3.5-4.5, 1.5-2.5 and 4.5-5.5 g/kg accounted for 25.2%, 5.1% and 1.0% respectively. The spatial distribution of the potential safety margin of salt and the maximum soil potential safety salinity showed a great corresponding relationship. The area with larger potential safety margin of salt has a larger maximum soil potential safety salinity at the same time, and vice versa.