漢代因解釋《春秋》而形成的公羊學派，受到古文學派的挑戰而逐漸沒落，遺說存世甚少。目前除了漢代一些文獻外，徐彥《公羊義疏》是僅存的公羊學派論釋《春秋》之材料。這部書後來被收入《十三經注疏》中，也可說是<<春秋，公羊傳>>最重要的疏解。不幸，千餘年來，徐彥這位作者固然身世成謎，本書是否為徐彥所作，也還有許多疑問；這部書之精神意趣、解經方法、具體觀點，更是罕見有人予以說明。 　　本文仍依舊說，暫定徐彥為唐朝人。一方面由其書概推唐代今文學的一般狀況（例如它與隋唐北宋今文家《孝經》學的關係）：二方面由徐彥解譯《春秋》的方法，說明它具有「聖典解經學」的性質，與「歷史解經學」頗為不同；三則分析它對《春秋》文字的解讀，如何形一種屬辭比事的詞例之學；四再討論公羊家所理解之「春秋大義」究竟為例，對孔子的治國理想到底有何闡述。 　　公羊夙稱絕學。其所以幾乎滅絕，是因為其政治主張頗與專制王權相枘鑿，也由於它的解經觀點與方法不易被理解，漢代以後，公羊學之發展更未受到關注，徐彥《公羊義疏》只是一個例子罷了。本文粗發其凡，足以見其大略。

　　　　　Challenged by the Kuwen School, the Kungyang School, which was formed by the Han Dynasty scholars explaining Confucisu' Chunchiu, faded out of the main trend of academic circles. Hence, it left us quite a few written materials. For the time being, except for a small amount of the Han Dynasty records, Yen Hsu's Kungyang-yishu 公羊義疏 (Notes on the Chunchiu-kungyang-chuan) is the only known document of the Kungyang School's Commentaries on Chunchiu remained. This book was later taken as a part of the Shihsan-chin-chushu 十三經注疏(Notes on the Thirteen Books). We can take it as the most importang notes on the Chunchiu-kungyang-chuan. Unfortunately, through over one thousand years, we not only do not know anything about Yen Hsu, but also have many doubts on the authenticity of his being the author. There had been even fewer studies on the book's interests, charms, methods of exploring the Chunchiu, and concrete viewpoint. This essay still takes Yen Hsu as a Tang Dynasty scholar according to the old theories. First, I will presume the general landscape of the Tang's Chingwen School. For instance, I will investigate its relationships with the Sui, Tand and Northern Sung Dynasties' Chingwen scholars' studies on the Canon of Filial Piety. Second, by studying the methodology of Yen Hsu's analysis on the Chunchiu, I will classify his Chunchiu-kungyang-chuan one of the Deifying the Classics in Explication, which is very different from the Historical Explication. Then, I will analyze how its interpretations on the Chunchiu formed an inductive grammar. Last, I will discuss the essence of the "Chunchiu-tayi 春秋大義 (Chunchiu's cardinal principles of righteousness)" comprehended by the Kungyang scholars, and their explications on Confucius' idealism of governing a country. The Kungyang School had always been called a lost art. The reasons of its extinction were its confrontation against the monarchy and its abstrusity in its explication. After Han Dynasty, the Kungyang School shared even fewer concerns. Yen Hsu's Notes on the Chunchiu-kungyang-chuan was only an example. Here I simply make a general start. Hopefully it will be a competent navigator.