Abstract: Influenced by global climate change and human activities, seawater intrusion and land subsidence have been important environmental problems in coastal areas. To study the potential effect of seawater intrusion on land subsidence, this paper conducted a series of one-dimensional lateral limit consolidation tests using high-purity quartz sand. The effects of the saline environment, the immersion environment and the consolidation environment on the creep of sand were investigated. Also, we qualitatively and quantitatively analyzed the breakage process and mechanism of the sand from a mesoscopic perspective. The results show that the saline environment can promote creep deformation of sand, and the promotion effect is more reflected in the consolidation process than in the immersion process. A higher concentration of salt solution usually leads to a significant promotion on sand creep. That is,seawater intrusion could potentially intensify land subsidence. The quantitative analysis of the mesoscopic structure images shows that, compared to non-saline environment, the saline environment may induce smaller pore areas, higher particle breakage rates and crack densities. Also, there are greater average shape factors of the particles and higher degrees of particle breakage. The presence of OH^- and Na⁺in weakly alkaline seawater promotes the hydrolysis of silica-oxygen bonds at the tips of quartz grains, which accelerates the development of sand particle cracks and further intensifies the breakage of sand particles. This paper reveals the macroscopic deformation law and the main mesoscopic mechanism of sand creep under saline environment, and elucidates that seawater intrusion may be a non-negligible factor affecting land subsidence in coastal areas.