Abstract: To study the solidification and improvement of silty clay in marine engineering under the environment of seawater erosion,different curing agents were used to solidify marine silt soil for indoor curing tests. For solidified soil of different proportions: cement-solidified soil(CS),steel slag powder-cement-solidified soil(SSP-CS),activator-steel slag powder-cement-solidified soil(A-SSP-CS),and slag powder-cement-solidified soil(SP-CS)were studied to analyze their physical and mechanical properties,the diffusion and distribution of erosion ions in solidified soil,and the changes of microstructure after erosion. The results show that the mass change rate of the samples cured by different curing agents fluctuates greatly with the increase of erosion time,and all of them show a trend of decreasing first and then increasing. After 90 days of erosion,the strength of each type of solidified soil reached the maximum value,and the strength of the SP-CS solidified soil sample was always much higher than that of other solidified soil samples from the initial stage. The comparison between SSP-CS and A-SSP-CS solidified soil samples shows that the internal compactness of A-SSP-CS solidified soil samples is reduced due to excessive activator NaOH,which results in a trend of decreasing strength. The transport and diffusion law of chloride ions shows that their content keeps increasing with the depth and age of erosion,the curve fluctuates greatly and steadily rises in the later period. The contrast of chloride ion concentration in the sample is :SP-CS>CS>SSP-CS>A-SSP-CS; In the SP-CS and SSP-CS solidified soil samples,hydration products such as C-S-H gelling and ATT acicular substances appear after seawater erosion,and the internal pores are small and closely arranged. The research results show that slag powder can replace cement to solidify silt soil feasibility,and can provide a theoretical basis for the study of the erosion resistance of solidified soil in practical engineering.