Ethics scholars in the dynasties of past times always worked hard in discussion of the content of social morality and individual moral. They established that moral principles have at least, the following three functions. 1. Moral principles are the accumulated long-time experience of life in human societies. 2. Clear definitions of individual responsibility and the methods of getting along with other people help people to behave well. 3.Moral goodness is strength. People have intense moral feeling have a broader vision field then people who have intelligence. Nevertheless, first, life is complicated and it is hard to live by simple principles. Secondly, principles can be explained in different way. Third, there are always exceptions. Fourth, some principles can mutually conflict. For example, people are born to equal so they have the same basic human rights, but the social resources are limited. If it depends on "the utilitarian principle" to assign resources, the benefit to disadvantaged minorities or minority groups must be reduced however if assignment of resources depends on "the equality principle", all people share the benefit but this inevitably will create insufficiency or waste of resources. Contemporary political thinker, John Rawls (1921~2002), believed that individuals should be allowed to pursue maximum individual satisfaction but society must have some powers to control how this is done, especially if it results in harm to others. But the "utilitarian principle" is never able properly to deal with this issue, therefore, Rawls wanted to substitute a new theory for "the utilitarian principle" which until now has been very popular, and to establish "the most suitable moral foundation" for politics and ethics.