Abstract: The supplementary illustrations in the Tao edition of Yingzao Fashi stand as the earliest scholarly accomplishment in the realm of Chinese architectural history since the rediscovery of the treatise. These illustrations are intricately linked to the four research principles put forward by Zhu Qiqian in the postscript of the reprinted edition: “mutual interpretation between Song and Qing dynasties”, “mathematical deduction”, “terminological illustration”, and “innovation in supplementary illustrations”, which collectively contributed to establishing the methodological groundwork for the Society for the Study of Chinese Architecture and Chinese architectural historical research by large. This paper adopts an intertextual dialogue and mutual-reference perspective to analyze the formation and practical application of these principles, aiming to elucidate the genuine academic significance of these illustrations, which have long been the subject of criticism in academic circles despite being provided by craftsmen.