Abstract: The functioning mechanism of groundwater and its make-up water in the process of ground subsidence was studied from such three aspects as osmotic corrasion, osmotic pressure effect and concretion effect. As to osmotic corrasion, its forming conditions, mechanical mechanism and process were analyzed. As to osmotic pressure effect, it was mainly studied from hydrostatic pressurizing effect, sop softening effect and negative pressure sealing effect. Through concretion and saturation of soil, the factors of concretion settlement were analyzed. The results showed that both groundwater and its make-up water are important triggering factors to ground subsidence.