The invention relates to the technical field of ecological restoration of coastal shoals and in particular relates to a method for adjusting and restoring seashore saline soil by brackish water. The method for adjusting and restoring the seashore saline soil by the brackish water comprises the following steps of: adding 2000kg-2600kg of phosphogypsum, 33m<3>-67m<3> of corn straws, 34m<3>-47m<3> of organic fertilizers, 200kg-300kg of high-activity humic acid and 200kg-300kg of zinc sulfate to every mu of soil after smoothing the soil; ploughing deeply for 30cm-35cm for sufficiently mixing the materials; uniformly irrigating underground brackish water with a degree of mineralization of not being more than 2g/l and a pH value of being 8.30-8.65 to the surface of the soil by adopting a drop-irrigation method, wherein the flow rate of a dripper is 0.5L per hour and the soil irrigation amount per mu is 190 m<3>-200m<3>. The method for adjusting and restoring seashore saline soil by brackish water not only can be used for adjusting the salt-alkali content of the soil, but also can be used for providing nutrient elements needed for the plant growth to improve the physical and chemical characteristics of the soil, so that the barren land of the coastal shoals reaches the soil environment which is suitable for the plant growth.