Abstract: AboutBook 3 A1 of the work Mencius,it is generally accepted that "taking human nature as good" is "the first meaning of Mengzi", and "commending Yao and Shun" is "the second section of cultivation". As a great chapter with significant value of examinations and interpretations, Book 3 A1 involves both literal-historical examinations and philosophical interpretations, which requires a two-pronged approach. Only under the new paradigm of single chapter study of Mencius, those little-known literal-historical examinations can draw deeper attention, and those well-known philosophical interpretations can be more extensively understood. In essence, accomplishing the study of the single chapter of Book 3 A1 is a real return to the field of thinking on "the first meaning of Mencius".