The philosophical trend had turned to metaphysics since the Tang Dynasty and developed to an approach that tried to interpret Taoism by Buddhism in the Sung Dynasty. The text of Lao Tze is simple but implies profound meaning. Everyone can cite authorities to make his comments on this classic. Scholars of the Sung Dynasty inclined to study Lao Tze from the aspect of Buddhism in two ways. On one hand, they would quote the Buddhism sutra directly, such as The Shurangama Sutra, The Vajra Prajna Paramita Sutra, The Sutra Preached by the Sixth Patriarch Hueneng, and Prajna Paramita Hear Sutra. On the other hand, they would refer to the Buddhism concepts, propositions and terminology and applied them to the theory of Taoism. This article discusses how the Buddhism concepts such as ”emptiness”, ”the real emptiness”, ”illusion” and discrimination” were used by the scholars in the Sung Dynasty to support the ideas implied in Lao Tze. The author also gives some examples of Buddhism terminology such as ”non-ego”, ”constancy”, ”without form”, ”six entrances”, ”the middle way”, ”the unique door to enlightenment”, ”birth and decease”, ”without clinging”, ”without remembrance”, ”without catch”, ”impermanent” and ”the Dharm Realm” that were frequently cited in the commentary of Lao Tze to illustrate the characteristics of philosophical trend in this period.
