This paper aims to interpret Dao De Ching(DDC)in terms of mathematical set theory.It employs the set study to demonstrate DDC,the first philosophy,the Chinese Bible.Properties of sets can well illustrate what is going on in this verse.DDC consists of a set of Dao and De,or a set of Dao,with all the components in the universe,the nature,or the human world,of which De can be rendered as its subset,the performances of myriad things.A host of terms,like Dao,De,Being(You),Non-being(Wu),Yin,Yang,Non-action(Wuwei),Spontaneity(Ziran),all are sets or subsets,fuzzy sets to be exact.Fields,group theory,Venn diagram,fuzzy sets all are playing substantial role in appreciating the book.DDC is a conjoined twin baby with a head(Ching)and two bodies(Dao and De);mathematics can dissect it.