Abstract: Although Shun Xiao in the book of hundred filial piety quotes Mencius's theory of "Great filial piety", there are differences between the two ideas of filial piety. Mencius is more inclined to believe that filial piety is not Poker Face to parents, it must have an emotional response, and will show it on the outside. Mencius disagrees with the Poker Face of parenthood, and with the idea that we are too close to each other to be ourselves. Mencius demonstrates his commitment to family values. On the dilemma between kinship and justice, Mencius argues that the principle of justice has limited limits on kinship and can not alter the order between parents and children due to changes in social status. In Mencius's view, political obligations have limits and limits, and the value of a "Lifetime of cheerfulness" for the self is higher than the value of political obligations. Mencius acknowledges that there is a side to man that transcends politics. Of course, the best case is to have both, in the"Heart", "To do" under the control of the state of mind to do human relations, including the family relationship and the emperor and subjects. A thorough study of these problems will help us grasp the relevant thoughts of pre-qin confucianists and clarify the theoretical difficulties and practical puzzles.