It is conceivable that the legal system of the Han Dynasty was always Confucian, which brought changes to the legal system and injected the moral spirit of Confucianism into laws and decrees. It makes the law have the nature of ethical law, that is, Confucianism is the guiding ideology and basic principle of legislation, annotation, conviction and sentencing in judicial practice. In the Han Dynasty, the ruling class carried out Confucianism in the whole process of legislation, judicature and law-abiding by introducing classics into prison and introducing rituals into the law, making Confucianism the basic principle and soul of criminal, civil, administrative and litigation departments, and making Confucian ethics gain legal effect and authority. As the beginning of Confucianism in China, the feudal legal system at that time had been deeply influenced by Confucianism.