Abstract: Monitoring results showed that the current land subsidence in wuxi area mainly comes from the aquitard, evaluating the compressibility of aquitard is very important, it make us know the development trend of land subsidence. This paper, which taked Quaternary soil layer in a drilling in wuxi Guangming village as the research object, used scanning electron microscope(SEM) to study the pore distribution characteristics of silty clay in different aquitard from micro-scale, and compared the result with the consolidation test data. The study found that the SEM image quantitative analysis result is correct and it can quantitatively indicate the amount of compressible pores and the complexity of the pores,; Porosity and the probability distribution index can reflect the pore density in soil and compressibility of soil. Research results can provided evidence for Suxichang regional land subsidence prediction from the microscopic.