The conservation of earthen sites in humid circumstances has always been a difficult subject. Sites exposed to the elements can easily be destroyed by heavy rain and water. Soil sites are also prone to cracking, as well as salt and powder-related damage even though protected by sheds. Furthermore, the use of chemical materials for consolidation during protection often results in peeling of the surface and other damage. In order to explore the severity and influence of various factors on relics diseases and to provide a basis for future research, we used the Kuahuqiao site in Hangzhou Xiaoshan as an example for investigation and study. We found that the roof covering the site can prevent the rain from destroying the soil, but the roof brings the problem of one-way transfer of water and salt, soil shrinkage and so on. In humid areas, because there are temperature differences between air and soil, water vapor condensation in the soil micropores is also an important cause of soil moisture, ease of cracking and salt deposition. Experimental studies on the water supply technologies for indoor soil sites need to be done as soon as possible.