本文旨在探討桐城派古文家—劉大櫆思想。桐城派是以孔、孟、韓、歐、程、朱之道自任，而與當時所謂漢學者相輕。今日談清代學術，多標舉「考據」為重要特色與成就，然而當時社會上，一般百姓仍是宗奉理學，乾嘉時期理學之發展與影響乃值得關注之課題。劉大櫆身居桐城二祖，其詩文是研究清代理學發展，及早期啟蒙思想的珍貴素材。經本文考察，得到以下幾點結論：一、劉大櫆之天道觀，主旨在說明「天道」渾然無知，而面對此渾然無知之天道，人唯求行其所當行，不計個人之殃慶窮通禍福；二、劉大櫆之性命觀，主張「盡其性，治其賊性之性」及「唯問分之所宜然，不問利益」之見解，仍是傳統理學的態度與立場；三、劉大櫆之倫理觀，以為君臣關係，僅是共事，是顛覆傳統理學「忠臣不事二君」之觀念；至於夫婦關係，他反對殉未婚夫，反對未嫁守節；四、劉大櫆對歷史極具懷疑精神，雖主張「世異則事異，時去則道殊」，但仍尊奉儒家道統。總而言之：其思想在保守中有進步，在拘執中有通達，隱隱間與整個大時代的學術脈動潛浮相契。

The purpose of this essay is to investigate the thought of Liu Da-kui, who was a leading member of the Tongcheng School of the Ancient Classics Movement. the Tongcheng School claimed to inherit the “Dao” of Confucius, Mencius, Han Yu, Ouyang Xiu, Cheng Yi, Zhu Xi, and criticized the so-call Han Xue School of their time. Nowadays “Textual study” is considered to be the most important feature and accomplishment of the Qing Dynasty. However, people of the Qing Dynasty still followed the teachings of Li Xue. Li Xue’s developments and influences during the times of Qianlong and Jiaqing reigns still deserve our attention. As the second leader of the Tongcheng School since its founding, Liu Da-kui’s poems and essays have become very precious materials for studying the developments of the Qing Dynasty Li Xue. This essay makes the following points: First, Liu Da-kui’s view on heavenly Way states that “heavenly Way” is comprehensive and objective. When facing this “heavenly Way”, human beings can only do what is right, and should not concern about fortunes or misfortunes, prosperity or difficulty of the individual. Second, Liu Da-kui’s view of human nature advocates that one should “fulfill one’s nature and get rid of one’s bad nature.” Moreover, he also maintains that “one should only concern about fulfilling one’s duty, and should not consider self-interest.” It is still following traditional Li Xue’s attitude and standpoint. Third, Liu Da-kui’s ethics considers the relationship between an emperor and ministers to be “colleagues”, which is opposite to Li Xue’s view, which claims that a loyal minister does not serve two lords. Regarding husband and wife, he opposes a woman to commit suicide for her husband before marriage or a woman should keep widowhood even if she is only engaged to her husband. Fourth, Liu Da-kui is skeptic of history. Although he thinks that “affairs change in all ages and as times change, the Way becomes different,” he still follows the orthodoxy of Confucianism. In summary, Liu Da-kui’s thought is not only conservative, but also progressive at the same time. From his thought, we can detect the currents or directions of the thought of the time.