Abstract: The deterioration of mural paintings in Takamatsuzuka Tumulus was not only caused by microorganisms like fungi, but also by spalling of lime plaster. Following excavation of mural paintings, the emergency preservation measures were applied to control the hygrothermal environment, however, without a visible success. To reduce the deterioration of mural paintings, one must reduce the frequency of wetting and drying cycles inside the chamber. Using climatic measurements, a numerical simulation of the effects of postexcavation preservation measures on hygrothermal behavior in the stone chambers of Takamatsuzuka Tumulus was performed. The results showed that the method of covering the exposed surface of the stone chamber with a certain thickness of soil will be more effective in limiting the temperature increases within the stone chamber and controlling dryness on the interior surfaces.