Abstract: Cultural properties are variously influenced by their surrounding environmental conditions. One of the reasons for the deterioration of mural paintings in the Takamatsuzuka Tumulus was the humid microclimate on their surface. In order to control the deterioration of mural paintings caused by such problems, it is important to investigate the environmental factors from various aspects, such as the temperature, humidity, water content of cultural properties, wetting and drying cycles and so on. As for the research concerning hygrothermal behavior on mural paintings, these variables may not be thoroughly predicted by 1-D or 2-D for determination of the location and degree of the deterioration of mural paintings. This paper shows how a 3-D hygrothermal model developed with a view to analyzing the preservation measures that allow quantifying of the degree of drying and condensing processes occurred on the surfaces of the underground chamber. The findings show that for the purpose of preserving mural paintings within the underground chamber, the temperature difference between the surrounding mound and the protected object should be kept as constant as can be practically achieved. This method is applicable for estimating the effects of preservation measures for the conservation of other mural paintings.