Abstract: Explanatory note is the core concept of LI Shan's annotation of "Wenxuan". Following the style of "Zuozhuan" in which explanatory notes are scattered in the annotations, LI Shan provided a thorough theoretical support for quoting books: According to the author's ancestral statement, the scholar's fashion and the annotation needs of literary reception, the temporal quotation follows the principle of quoting before, the same time and after; on the basis of giving consideration to the annotation accuracy and reading experience, the spatial layout of the citations in the whole book is avoiding repetition. LI Shan internalized XIAO tong's compilation principles and tried to coordinate the conflict between the previous notes and "Wenxuan" by setting three levels of credit rating of the pre-vious notes, namely, accurate notes, defective notes and rough notes. In the practice of annotation, LI Shan also eased the contradiction between the explanatory notes and "Wenxuan", the previous notes and the notes of LI Shan himself by means of conditional interpretation and additional variations. The explanatory note on "Wenxuan" is an important factor for LI Shan's annotation to become a model of the quotation type of exegesis, which has promoted the status of the literary collections in academic methods.