Researches of ancient Chinese philosophy have become popular within the academic field nowadays, especially in the Western world. The study of ancient Chinese philosophers, indeed, provided a critical insight for scholars to understand Chinese philosophy and history. This paper examines three renowned ancient Chinese philosophers, namely Mencius, Xunzi and Han Feizi, which is conducive to outline the evolution of the discussion of the ideas of human nature and political governance across the warring-state period. By studying their philosophical origins and perspectives, this paper reexamines the ancient classical compositions and existing analyses and contributes to the academic domain in threefold. It provided a comprehensive elucidation of the above philosophers' arguments, both origins and core values, compared and contrasted the philosophical ideas among them, as well as illuminated the misconceptions or misinterpretations on current scholastic literatures.