Abstract: With the large-scale development of water conservancy projects in my country, marine silt has a certain impact on the offshore environment and the construction and maintenance of engineering facilities, and affects ports and waterway transportation. Therefore, a large amount of marine silt is urgently awaiting treatment and utilization. This paper explores the relationship between soil pH,soil salinity and leaching amount through leaching tests, and using admixtures composed of straw, sand, biochar, organic fertilizer, desulfurized gypsum and other materials to modify marine sludge test. The results of the study showed that the soil pH value and soil salt content of the sample soil fell within the standard value after the intermittent 1000 mL leaching volume; the soil alkalinity did not decrease but slightly increased at the beginning of leaching; the salt content decreases with the increase of the number of leaching. During the intermediate stage(4 to 8 times) of leaching, due to the formation of seepage channels in the soil column, the efficiency of reducing the soil salt content decreases. The marine sludge was first leached and "washed with salt", and admixtures were added to modify the marine sludge. After modification, it was suitable for plant growth, which verified the feasibility of modified marine sludge for planting soil.