Sun Sheng (307-378) was an important historian and thinker of the mid-Eastern Chin dynasty. The main trend of Eastern-Chin hsiianhsiieh, after Kuo Hsiang's interpretation of the Chuang Tzu, was a syncretism of Confucianism and Taoism. Most thinkers of the time dwelled in the real world, paying particular attention to the relation between “affection” and “rite.” With perspectives from the commentarial tradition and a reflection on the so-called liberating atmosphere of this period, looking at it in the context of the overall development of hsiianhsiieh, we can better comprehend the meaning of this syncretism. . This paper studies Sun Sheng's thought and his essays, “Lao-tzu iwen fan-hsiln” and “Lao-tan fei ta-hsien lun.” The author offers discussions of why Sun Sheng was so ardently against Lao Tzu by comparing Sun Sheng and Wang Pi's works. Wang Pi contributed the concept of “original non-being” (pen-wu) to Taoism. Accordingly, all beings originated from non-being, hence non-being was an innate nature of all beings. The substance (non-being, ti) and the appearance (being, yung) are the two aspects of Tao, partaking of “mystery” (hsilan). Indeed, Tao is the mystery of all mysteries. In Sun's interpretation, the concept of Tao expressed in the Lao Tzu is contradictory, since Lao Tzu preferred the significance of non-being to every being. This paper argues that Sun Sheng's comprehension of Lao Tzu's thought is limited, and that Sun seemed to have no acquaintance with Wang Pi's commentary on the Lao Tzu. In the conclusion, the author evaluates Sun Sheng's thought expressed in the essays in the context of the history of hsiian-hsileh in the Wei-Chin period.