Plato is one of the greatest philosophers in ancient Greek in the western world and he created the first political-philosophy in the philosophical history.In the early times,for his advanced education,Plato was determined to set up his ideal country.After his dream was smashed,he realized that governing a country with only morality couldn't work and rule of law was quite necessary.And when he grew older,he had always been immersed morality and thought that rule of morality was better than law.He thus was in dilemma on those viewpoints of ideal and reality,theory and practice.What we should learn from him is his seeking for moral governing all the time.