Confucius first proposed "education without class", which broke the social hierarchy and made education open to the public to a certain extent. In teaching practice, he emphasized "teaching people tirelessly" and "following good advice". Be good at heuristic teaching, attach importance to students' subjective initiative, and give guidance when students have problems. Educate students to draw inferences from one to the other, "draw inferences from the other" and "draw inferences from the other". Pay attention to teaching students in accordance with their aptitude, and often give different answers according to different situations of students. He taught his disciples: "Knowing is knowing, not knowing is not knowing, but knowing." (Politics) advocates studying hard and asking more questions, but he himself is "never tired of learning", "angry and forgetting food, happy and forgetting worries", "suspicious and cautious about rest", "quick and eager to learn, not ashamed to ask". In his view, as long as you are good at learning, there are teachers everywhere. "In a threesome, there must be a teacher, choose the good and follow it, and change it." (Shu Er) emphasizes the combination of learning and thinking, and thinking is based on learning. It is required to combine absorbing new knowledge with reviewing existing knowledge, match words with deeds, and oppose empty talk, saying nothing but doing nothing. Many of Confucius' insights are still very useful today.