Decoration is an important factor of a building’s external appearance. Not many exterior decorative elements have survived dating prior to the Yuan dynasty, but Song and Yuan paintings often depict them. Through image analysis, extracting meaningful information from these images, combined with the specififications recorded in Song building standards (Yingzao fashi) and other historical texts， this paper discusses the form, installation, and use of several decorative elements such as piliangan, bifengta, zhangrita, and yinyan, as well as the diversifified architectural appearance produced by them.