The Dunhuang Grottoes, located on the ancient Silk Road, can be considered a precious warehouse of the various pigments used between the 4th and 14th centuries. The wall paintings in the grottoes there show periodical changes in pigments. Modern scientific analysis has revealed the use of three kinds of pigments in the grottoes: mineral. organic, and chemical pigments. Mineral pigments were extracted from minerals and refined to use in the paintings. Most of the paintings in Dunhuang were executed in mineral pigments, which have shown to have a long preservation period. Of the organic pigments on black ink has a preservation period comparable to mineral pigments. Chemical pigments allowed for various textures and for mixing color. Research by the Duhuang Cultural Institute and other institutions since the late 1970s has provided evidence for the origin of these pigments. and cultural. trade, and scientific exchange between the east and west. Such research will be beneficial to understanding traditional Korean wall pigments, as well. It would be impossible to describe all of the results of research on Dunhuang pigments in this thesis. Therefore, in this thesis I have focussed on the cause of the change of white lead and red lead pigments in Dunhuang into dark brown and grey, Earlier books of art history have shown that when silver red was mixed with white lead or white color, the change to black due to oxidation was the result of the silver red. I would like to correct this information into that if red lead used only in wall paintings, it might produce lead peroxide to change into black. and if red lead and white lead mixed together in the painting, red lead produce lead peroxide after natural oxidation to change into black. Recent scientific analysis shows that the main factor to change into black was the lead peroxide. Furthermore, many research show that the area which were painted with silver red only didn't change their color. According to documents recently discovered by Chinese archaeologists. lead was used from the Chin Dynasty. There are evidence in Emperor Chin's terracotta army. silk paintings, many tombs. grottoes. and temples which wen, changed red lead into black. Therefore. Chinese conservators are developing techniques to protect white lead and red lead to be changed into black.