This lecture provides a brief introduction to the phenomenon of the "Letting a Hundred Schools of Thought Contend" in the Spring and Autumn and Warring States Periods (771-256BC) in Chinese history. It introduces the main schools of philosophy in ancient China: Confucianism, Taoism, Mohism and Legalism, and the main ideas of their founders, Confucius and Laozi. You can begin to understand the main philosophical schools of ancient China and their representatives, as well as their influence on later generations. Perhaps you will slowly come to understand the traditional thinking of the Chinese. After all, understanding is the key to successful communication.