As a cross-science-art subject, the main content of the science of conservation of cultural relics discussed here includes studies on preservation and restoration technology of cultural relics and on the properties of the related materials. Emphasis has been put on the methodology of the science of conservation of cultural relics. Proper and efficient way of preservation and sutable remedy to the case can be developed only by studying at first the preserving environment and properties of materials of cultural relics, as well as pathological changes of the cultural relics, while the cultural relics had been preserved. Also discussed is the important role that the research on environment plays in the preservation of cultural relics. The relationship among the environment, material, restoration technology and basic principles supposed to be obeyed in preserving culture relics are as well briefly discussed.