Plato is also the first person in the history of western education to put forward a complete pre-school education thought and establish a complete education system. Plato began to engage in educational research activities in middle age. Starting from the philosophical thought that idea precedes matter, he emphasized rational exercise in the education system. He put children aged 3-6 under the care of nannies, and they would gather in the village temple to play games and listen to stories and fairy tales. Plato thinks these are very instructive. After the age of 7, children will begin to learn all kinds of knowledge and skills that soldiers need, including reading, writing, calculating, riding, throwing guns, archery and so on. From the age of 20 to 30, those students who show special interest in abstract thinking will continue their studies and learn arithmetic, geometry, astronomy and acoustics, so as to exercise their thinking ability and make them begin to explore the mysteries of the universe. Plato pointed out the significance of each subject to the development of abstract thinking. He advocates that future rulers should further study dialectics after the age of 30 to gain insight into the world of thought. In five years, he can be the king of philosophy that rules the country.