Abstract: It is a challenge for the conservation of soil ruin sites that molds grow on the surface of damp soil ruins in soil ruin exhibition halls in high-humidity regions. The ventilation and lighting modes of soil ruin exhibition halls directly affect mold reproduction, but studies on the quantitative relationship between environmental factors and mold propagation on surfaces in damp soil ruins are insufficient. The Wenzhou Qiaolou soil ruin was selected as an example in this study, and rammed earth from this ruin was used as the experiment sample. For the ventilation and lighting modes as experimental variables, four ventilation and lighting environmental conditions were simulated for 56 days in a laboratory to compare differences in mold growth on samples of damp rammed earth surfaces. In this study, the difference of mold growth in different ventilation and lighting conditions were discussed, and some suggestions for the environmental management of soil ruin exhibition halls in high-humidity regions were given.