Abstract: As the utilitarianism is rampant in the Warring States Period, Mencius wants to fight against the world and saves the world, fighting with three discrimination as powerful weapons, the Human-Animal Distinction, the Justice-Interest Distinction, and the Kingly Way-Hegemonic Way Distinction, for Creating peace for the world in the period. From this perspective to study the philosophy of Mencius, We can clarify a lot misunderstandings by the scholars of all ages in Chinese history, and avoid overly accusing the ancients. In particular, it can be clearly judged which is the original meaning of Mencius, and which is not, and the meaning that can be inferred from the original meaning of Mencius, so as to restore the true features of Mencius' thought.